. Update the Copyright year (only) when changing content.
. /////////////////////////////////////////////////////////////////////////////
-.set previousversion "4.95"
+.set previousversion "4.96"
.include ./local_params
.set ACL "access control lists (ACLs)"
.set drivernamemax "64"
.macro copyyear
-2021
+2022
.endmacro
. /////////////////////////////////////////////////////////////////////////////
.itable none 0 0 2 $1 left $2 left
.endmacro
+
+. --- A macro for a plain variable, including the .vitem and .vindex
+.macro var
+.vitem $1
+.vindex $1
+.endmacro
+
+. --- A macro for a "tainted" marker, done as a one-element table
+.macro tmark
+.itable none 0 0 1 10pt left
+.row &'Tainted'&
+.endtable
+.endmacro
+
+. --- A macro for a tainted variable, adding a taint-marker
+.macro tvar
+.var $1
+.tmark
+.endmacro
+
+. --- A macro for a cmdline option, including a .oindex
+. --- 1st arg is the option name, undecorated (we do that here).
+. --- 2nd arg, optional, text (decorated as needed) to be appended to the name
+.macro cmdopt
+.vitem &%$1%&$=2+&~$2+
+.oindex &%$1%&
+.endmacro
+
. --- A macro that generates .row, but puts &I; at the start of the first
. --- argument, thus indenting it. Assume a minimum of two arguments, and
. --- allow up to four arguments, which is as many as we'll ever need.
. --- style of entry, use .scindex for the start and .ecindex for the end. The
. --- first argument of .scindex and the only argument of .ecindex must be the
. --- ID that ties them together.
+. --- The index entry points to the most-recent chapter head, section or subsection
+. --- head, or list-item.
.macro cindex
&<indexterm role="concept">&
&</indexterm>&
.endmacro
+. --- The index entry points to the most-recent chapter head, section or subsection
+. --- head, or varlist item.
+
.macro vindex
&<indexterm role="variable">&
&<primary>&$1&</primary>&
. /////////////////////////////////////////////////////////////////////////////
-. This chunk of literal XML implements index entries of the form "x, see y" and
-. "x, see also y". However, the DocBook DTD doesn't allow <indexterm> entries
+. These implement index entries of the form "x, see y" and "x, see also y".
+. However, the DocBook DTD doesn't allow <indexterm> entries
. at the top level, so we have to put the .chapter directive first.
-
-. These do not turn up in the HTML output, unfortunately. The PDF does get them.
. /////////////////////////////////////////////////////////////////////////////
.chapter "Introduction" "CHID1"
-.literal xml
-<indexterm role="variable">
- <primary>$1, $2, etc.</primary>
- <see><emphasis>numerical variables</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>address</primary>
- <secondary>rewriting</secondary>
- <see><emphasis>rewriting</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>Bounce Address Tag Validation</primary>
- <see><emphasis>BATV</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>Client SMTP Authorization</primary>
- <see><emphasis>CSA</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>CR character</primary>
- <see><emphasis>carriage return</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>CRL</primary>
- <see><emphasis>certificate revocation list</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>delivery</primary>
- <secondary>failure report</secondary>
- <see><emphasis>bounce message</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>dialup</primary>
- <see><emphasis>intermittently connected hosts</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>exiscan</primary>
- <see><emphasis>content scanning</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>failover</primary>
- <see><emphasis>fallback</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>fallover</primary>
- <see><emphasis>fallback</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>filter</primary>
- <secondary>Sieve</secondary>
- <see><emphasis>Sieve filter</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>ident</primary>
- <see><emphasis>RFC 1413</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>LF character</primary>
- <see><emphasis>linefeed</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>maximum</primary>
- <seealso><emphasis>limit</emphasis></seealso>
-</indexterm>
-<indexterm role="concept">
- <primary>monitor</primary>
- <see><emphasis>Exim monitor</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>no_<emphasis>xxx</emphasis></primary>
- <see>entry for xxx</see>
-</indexterm>
-<indexterm role="concept">
- <primary>NUL</primary>
- <see><emphasis>binary zero</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>passwd file</primary>
- <see><emphasis>/etc/passwd</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>process id</primary>
- <see><emphasis>pid</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>RBL</primary>
- <see><emphasis>DNS list</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>redirection</primary>
- <see><emphasis>address redirection</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>return path</primary>
- <seealso><emphasis>envelope sender</emphasis></seealso>
-</indexterm>
-<indexterm role="concept">
- <primary>scanning</primary>
- <see><emphasis>content scanning</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>SSL</primary>
- <see><emphasis>TLS</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>string</primary>
- <secondary>expansion</secondary>
- <see><emphasis>expansion</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>top bit</primary>
- <see><emphasis>8-bit characters</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>variables</primary>
- <see><emphasis>expansion, variables</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>zero, binary</primary>
- <see><emphasis>binary zero</emphasis></see>
-</indexterm>
-<indexterm role="concept">
- <primary>headers</primary>
- <see><emphasis>header lines</emphasis></see>
+.macro seeother
+.literal xml
+<indexterm role="$2">
+ <primary>$3</primary>
+.arg 5
+ <secondary>$5</secondary>
+.endarg
+ <$1><emphasis>$4</emphasis></$1>
</indexterm>
-
.literal off
+.endmacro
+
+. NB: for the 4-arg variant the ordering is awkward
+.macro see
+.seeother see "$1" "$2" "$3" "$4"
+.endmacro
+.macro seealso
+.seeother seealso "$1" "$2" "$3" "$4"
+.endmacro
+
+.see variable "<emphasis>$1</emphasis>, <emphasis>$2</emphasis>, etc." "numerical variables"
+.see concept address rewriting rewriting
+.see concept "Bounce Address Tag Validation" BATV
+.see concept "Client SMTP Authorization" CSA
+.see concept "CR character" "carriage return"
+.see concept CRL "certificate revocation list"
+.seealso concept de-tainting "tainted data"
+.see concept delivery "bounce message" "failure report"
+.see concept dialup "intermittently connected hosts"
+.see concept exiscan "content scanning"
+.see concept fallover fallback
+.see concept filter "Sieve filter" Sieve
+.see concept headers "header lines"
+.see concept ident "RFC 1413"
+.see concept "LF character" "linefeed"
+.seealso concept maximum limit
+.see concept monitor "Exim monitor"
+.see concept "no_<emphasis>xxx</emphasis>" "entry for xxx"
+.see concept NUL "binary zero"
+.see concept "passwd file" "/etc/passwd"
+.see concept "process id" pid
+.see concept RBL "DNS list"
+.see concept redirection "address redirection"
+.see concept "return path" "envelope sender"
+.see concept scanning "content scanning"
+.see concept SSL TLS
+.see concept string expansion expansion
+.see concept "top bit" "8-bit characters"
+.see concept variables "expansion, variables"
+.see concept "zero, binary" "binary zero"
. /////////////////////////////////////////////////////////////////////////////
order in which they are tested. The individual configuration options are
described in more detail in chapter &<<CHAProutergeneric>>&.
-.ilist
+.olist
.cindex affix "router precondition"
The &%local_part_prefix%& and &%local_part_suffix%& options can specify that
the local parts handled by the router may or must have certain prefixes and/or
If the &%domains%& option is set, the domain of the address must be in the set
of domains that it defines.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using router domains option"
A match verifies the variable &$domain$& (which carries tainted data)
and assigns an untainted value to the &$domain_data$& variable.
Such an untainted value is often needed in the transport.
.cindex "delivery" "in detail"
When a message is to be delivered, the sequence of events is as follows:
-.ilist
+.olist
If a system-wide filter file is specified, the message is passed to it. The
filter may add recipients to the message, replace the recipients, discard the
message, cause a new message to be generated, or cause the message delivery to
-.section "Temporary delivery failure" "SECID20"
+.subsection "Temporary delivery failure" SECID20
.cindex "delivery" "temporary failure"
There are many reasons why a message may not be immediately deliverable to a
particular address. Failure to connect to a remote machine (because it, or the
-.section "Permanent delivery failure" "SECID21"
+.subsection "Permanent delivery failure" SECID21
.cindex "delivery" "permanent failure"
.cindex "bounce message" "when generated"
When a message cannot be delivered to some or all of its intended recipients, a
-.section "Failures to deliver bounce messages" "SECID22"
+.subsection "Failures to deliver bounce messages" SECID22
.cindex "bounce message" "failure to deliver"
If a bounce message (either locally generated or received from a remote host)
itself suffers a permanent delivery failure, the message is left in the queue,
To complicate things further, there are several very different versions of the
Berkeley DB package. Version 1.85 was stable for a very long time, releases
2.&'x'& and 3.&'x'& were current for a while,
-.new
but the latest versions when Exim last revamped support were numbered 5.&'x'&.
Maintenance of some of the earlier releases has ceased,
and Exim no longer supports versions before 3.&'x'&.
-.wen
All versions of Berkeley DB could be obtained from
&url(http://www.sleepycat.com/), which is now a redirect to their new owner's
page with far newer versions listed.
.endd
Similarly, for gdbm you set USE_GDBM, and for tdb you set USE_TDB. An
error is diagnosed if you set more than one of these.
-.new
You can set USE_NDBM if needed to override an operating system default.
-.wen
At the lowest level, the build-time configuration sets none of these options,
thereby assuming an interface of type (1). However, some operating system
DBMLIB = -ltdb
DBMLIB = -lgdbm -lgdbm_compat
.endd
-.new
The last of those was for a Linux having GDBM provide emulated NDBM facilities.
-.wen
Settings like that will work if the DBM library is installed in the standard
place. Sometimes it is not, and the library's header file may also not be in
the default path. You may need to set INCLUDE to specify where the header
.vlist
-.vitem &%--%&
-.oindex "--"
+.cmdopt "--" "--"
.cindex "options" "command line; terminating"
This is a pseudo-option whose only purpose is to terminate the options and
therefore to cause subsequent command line items to be treated as arguments
rather than options, even if they begin with hyphens.
-.vitem &%--help%&
-.oindex "&%--help%&"
+.cmdopt --help
This option causes Exim to output a few sentences stating what it is.
The same output is generated if the Exim binary is called with no options and
no arguments.
-.vitem &%--version%&
-.oindex "&%--version%&"
+.cmdopt --version
This option is an alias for &%-bV%& and causes version information to be
displayed.
These options are used by Sendmail for selecting configuration files and are
ignored by Exim.
-.vitem &%-B%&<&'type'&>
+.cmdopt -B <&'type'&>
.oindex "&%-B%&"
.cindex "8-bit characters"
.cindex "Sendmail compatibility" "8-bit characters"
This is a Sendmail option for selecting 7 or 8 bit processing. Exim is 8-bit
clean; it ignores this option.
-.vitem &%-bd%&
-.oindex "&%-bd%&"
+.cmdopt -bd
.cindex "daemon"
.cindex "SMTP" "listener"
.cindex "queue runner"
referenced from the configuration (for example, alias files) are changed,
because these are reread each time they are used.
-.vitem &%-bdf%&
-.oindex "&%-bdf%&"
+.cmdopt -bdf
This option has the same effect as &%-bd%& except that it never disconnects
from the controlling terminal, even when no debugging is specified.
-.vitem &%-be%&
-.oindex "&%-be%&"
+.cmdopt -be
.cindex "testing" "string expansion"
.cindex "expansion" "testing"
Run Exim in expansion testing mode. Exim discards its root privilege, to
Because macros in the config file are often used for secrets, those are only
available to admin users.
-.vitem &%-bem%&&~<&'filename'&>
-.oindex "&%-bem%&"
+.new
+The word &"set"& at the start of a line, followed by a single space,
+is recognised specially as defining a value for a variable.
+The syntax is otherwise the same as the ACL modifier &"set ="&.
+.wen
+
+.cmdopt -bem <&'filename'&>
.cindex "testing" "string expansion"
.cindex "expansion" "testing"
This option operates like &%-be%& except that it must be followed by the name
line, because further arguments are taken as strings to expand (just like
&%-be%&).
-.vitem &%-bF%&&~<&'filename'&>
-.oindex "&%-bF%&"
+.cmdopt -bF <&'filename'&>
.cindex "system filter" "testing"
.cindex "testing" "system filter"
This option is the same as &%-bf%& except that it assumes that the filter being
tested is a system filter. The additional commands that are available only in
system filters are recognized.
-.vitem &%-bf%&&~<&'filename'&>
-.oindex "&%-bf%&"
+.cmdopt -bf <&'filename'&>
.cindex "filter" "testing"
.cindex "testing" "filter file"
.cindex "forward file" "testing"
can be set by means of additional command line options (see the next four
options).
-.vitem &%-bfd%&&~<&'domain'&>
-.oindex "&%-bfd%&"
+.cmdopt -bfd <&'domain'&>
.vindex "&$qualify_domain$&"
This sets the domain of the recipient address when a filter file is being
tested by means of the &%-bf%& option. The default is the value of
&$qualify_domain$&.
-.vitem &%-bfl%&&~<&'local&~part'&>
-.oindex "&%-bfl%&"
+.cmdopt -bfl <&'local&~part'&>
This sets the local part of the recipient address when a filter file is being
tested by means of the &%-bf%& option. The default is the username of the
process that calls Exim. A local part should be specified with any prefix or
suffix stripped, because that is how it appears to the filter when a message is
actually being delivered.
-.vitem &%-bfp%&&~<&'prefix'&>
-.oindex "&%-bfp%&"
+.cmdopt -bfp <&'prefix'&>
.cindex affix "filter testing"
This sets the prefix of the local part of the recipient address when a filter
file is being tested by means of the &%-bf%& option. The default is an empty
prefix.
-.vitem &%-bfs%&&~<&'suffix'&>
-.oindex "&%-bfs%&"
+.cmdopt -bfs <&'suffix'&>
.cindex affix "filter testing"
This sets the suffix of the local part of the recipient address when a filter
file is being tested by means of the &%-bf%& option. The default is an empty
suffix.
-.vitem &%-bh%&&~<&'IP&~address'&>
-.oindex "&%-bh%&"
+.cmdopt -bh <&'IP&~address'&>
.cindex "testing" "incoming SMTP"
.cindex "SMTP" "testing incoming"
.cindex "testing" "relay control"
specialized SMTP test program such as
&url(https://www.jetmore.org/john/code/swaks/,swaks).
-.vitem &%-bhc%&&~<&'IP&~address'&>
-.oindex "&%-bhc%&"
+.cmdopt -bhc <&'IP&~address'&>
This option operates in the same way as &%-bh%&, except that address
verification callouts are performed if required. This includes consulting and
updating the callout cache database.
-.vitem &%-bi%&
-.oindex "&%-bi%&"
+.cmdopt -bi
.cindex "alias file" "building"
.cindex "building alias file"
.cindex "Sendmail compatibility" "&%-bi%& option"
&%-bi%& is a no-op.
. // Keep :help first, then the rest in alphabetical order
-.vitem &%-bI:help%&
-.oindex "&%-bI:help%&"
+.cmdopt -bI:help
.cindex "querying exim information"
We shall provide various options starting &`-bI:`& for querying Exim for
information. The output of many of these will be intended for machine
synopsis of supported options beginning &`-bI:`&. Use of any of these
options shall cause Exim to exit after producing the requested output.
-.vitem &%-bI:dscp%&
-.oindex "&%-bI:dscp%&"
+.cmdopt -bI:dscp
.cindex "DSCP" "values"
This option causes Exim to emit an alphabetically sorted list of all
recognised DSCP names.
-.vitem &%-bI:sieve%&
-.oindex "&%-bI:sieve%&"
+.cmdopt -bI:sieve
.cindex "Sieve filter" "capabilities"
This option causes Exim to emit an alphabetically sorted list of all supported
Sieve protocol extensions on stdout, one per line. This is anticipated to be
compile-time build options, which this option will adapt to, this is the only
way to guarantee a correct response.
-.vitem &%-bm%&
-.oindex "&%-bm%&"
+.cmdopt -bm
.cindex "local message reception"
This option runs an Exim receiving process that accepts an incoming,
locally-generated message on the standard input. The recipients are given as the
preference to the address taken from the message. The caller of Exim must be a
trusted user for the sender of a message to be set in this way.
-.vitem &%-bmalware%&&~<&'filename'&>
-.oindex "&%-bmalware%&"
+.cmdopt -bmalware <&'filename'&>
.cindex "testing", "malware"
.cindex "malware scan test"
This debugging option causes Exim to scan the given file or directory
there are better tools for file-scanning. This option exists to help
administrators verify their Exim and AV scanner configuration.
-.vitem &%-bnq%&
-.oindex "&%-bnq%&"
+.cmdopt -bnq
.cindex "address qualification, suppressing"
By default, Exim automatically qualifies unqualified addresses (those
without domains) that appear in messages that are submitted locally (that
unqualified addresses in header lines are left alone.
-.vitem &%-bP%&
-.oindex "&%-bP%&"
+.cmdopt -bP
.cindex "configuration options" "extracting"
.cindex "options" "configuration &-- extracting"
If this option is given with no arguments, it causes the values of all Exim's
For the "-bP macro <name>" form, if no such macro is found
the exit status will be nonzero.
-.vitem &%-bp%&
-.oindex "&%-bp%&"
+.cmdopt -bp
.cindex "queue" "listing messages in"
.cindex "listing" "messages in the queue"
This option requests a listing of the contents of the mail queue on the
complete.
-.vitem &%-bpa%&
-.oindex "&%-bpa%&"
+.cmdopt -bpa
This option operates like &%-bp%&, but in addition it shows delivered addresses
that were generated from the original top level address(es) in each message by
alias or forwarding operations. These addresses are flagged with &"+D"& instead
of just &"D"&.
-.vitem &%-bpc%&
-.oindex "&%-bpc%&"
+.cmdopt -bpc
.cindex "queue" "count of messages on"
This option counts the number of messages in the queue, and writes the total
to the standard output. It is restricted to admin users, unless
&%queue_list_requires_admin%& is set false.
-.vitem &%-bpr%&
-.oindex "&%-bpr%&"
+.cmdopt -bpr
This option operates like &%-bp%&, but the output is not sorted into
chronological order of message arrival. This can speed it up when there are
lots of messages in the queue, and is particularly useful if the output is
going to be post-processed in a way that doesn't need the sorting.
-.vitem &%-bpra%&
-.oindex "&%-bpra%&"
+.cmdopt -bpra
This option is a combination of &%-bpr%& and &%-bpa%&.
-.vitem &%-bpru%&
-.oindex "&%-bpru%&"
+.cmdopt -bpru
This option is a combination of &%-bpr%& and &%-bpu%&.
-.vitem &%-bpu%&
-.oindex "&%-bpu%&"
+.cmdopt -bpu
This option operates like &%-bp%& but shows only undelivered top-level
addresses for each message displayed. Addresses generated by aliasing or
forwarding are not shown, unless the message was deferred after processing by a
router with the &%one_time%& option set.
-.vitem &%-brt%&
-.oindex "&%-brt%&"
+.cmdopt -brt
.cindex "testing" "retry configuration"
.cindex "retry" "configuration testing"
This option is for testing retry rules, and it must be followed by up to three
Retry rule: *@haydn.comp.mus.example quota_3d F,1h,15m
.endd
-.vitem &%-brw%&
-.oindex "&%-brw%&"
+.cmdopt -brw
.cindex "testing" "rewriting"
.cindex "rewriting" "testing"
This option is for testing address rewriting rules, and it must be followed by
would be rewritten for each possible place it might appear. See chapter
&<<CHAPrewrite>>& for further details.
-.vitem &%-bS%&
-.oindex "&%-bS%&"
+.cmdopt -bS
.cindex "SMTP" "batched incoming"
.cindex "batched SMTP input"
This option is used for batched SMTP input, which is an alternative interface
More details of input using batched SMTP are given in section
&<<SECTincomingbatchedSMTP>>&.
-.vitem &%-bs%&
-.oindex "&%-bs%&"
+.cmdopt -bs
.cindex "SMTP" "local input"
.cindex "local SMTP input"
This option causes Exim to accept one or more messages by reading SMTP commands
Exim behaves in exactly the same way as it does when receiving a message via
the listening daemon.
-.vitem &%-bt%&
-.oindex "&%-bt%&"
+.cmdopt -bt
.cindex "testing" "addresses"
.cindex "address" "testing"
This option runs Exim in address testing mode, in which each argument is taken
those conditions using &%-bt%&. The &%-N%& option provides a possible way of
doing such tests.
-.vitem &%-bV%&
-.oindex "&%-bV%&"
+.cmdopt -bV
.cindex "version number of Exim"
This option causes Exim to write the current version number, compilation
number, and compilation date of the &'exim'& binary to the standard output.
realistic testing is needed. The &%-bh%& and &%-N%& options provide more
dynamic testing facilities.
-.vitem &%-bv%&
-.oindex "&%-bv%&"
+.cmdopt -bv
.cindex "verifying address" "using &%-bv%&"
.cindex "address" "verification"
This option runs Exim in address verification mode, in which each argument is
sender when running &%-bv%& tests. Without it, the sender is assumed to be the
calling user at the default qualifying domain.
-.vitem &%-bvs%&
-.oindex "&%-bvs%&"
+.cmdopt -bvs
This option acts like &%-bv%&, but verifies the address as a sender rather
than a recipient address. This affects any rewriting and qualification that
might happen.
-.vitem &%-bw%&
-.oindex "&%-bw%&"
+.cmdopt -bw
.cindex "daemon"
.cindex "inetd"
.cindex "inetd" "wait mode"
If the option is given as &%-bw%&<&'time'&> then the time is a timeout, after
which the daemon will exit, which should cause inetd to listen once more.
-.vitem &%-C%&&~<&'filelist'&>
-.oindex "&%-C%&"
+.cmdopt -C <&'filelist'&>
.cindex "configuration file" "alternate"
.cindex "CONFIGURE_FILE"
.cindex "alternate configuration file"
debugging, whereas &%-d-all+filter%& selects only filter debugging. Note that
no spaces are allowed in the debug setting. The available debugging categories
are:
-.display
-&`acl `& ACL interpretation
-&`auth `& authenticators
-&`deliver `& general delivery logic
-&`dns `& DNS lookups (see also resolver)
-&`dnsbl `& DNS black list (aka RBL) code
-&`exec `& arguments for &[execv()]& calls
-&`expand `& detailed debugging for string expansions
-&`filter `& filter handling
-&`hints_lookup `& hints data lookups
-&`host_lookup `& all types of name-to-IP address handling
-&`ident `& ident lookup
-&`interface `& lists of local interfaces
-&`lists `& matching things in lists
-&`load `& system load checks
-&`local_scan `& can be used by &[local_scan()]& (see chapter &&&
- &<<CHAPlocalscan>>&)
-&`lookup `& general lookup code and all lookups
-&`memory `& memory handling
-&`noutf8 `& modifier: avoid UTF-8 line-drawing
-&`pid `& modifier: add pid to debug output lines
-&`process_info `& setting info for the process log
-&`queue_run `& queue runs
-&`receive `& general message reception logic
-&`resolver `& turn on the DNS resolver's debugging output
-&`retry `& retry handling
-&`rewrite `& address rewriting
-&`route `& address routing
-&`timestamp `& modifier: add timestamp to debug output lines
-&`tls `& TLS logic
-&`transport `& transports
-&`uid `& changes of uid/gid and looking up uid/gid
-&`verify `& address verification logic
-&`all `& almost all of the above (see below), and also &%-v%&
-.endd
+.itable none 0 0 2 20* left 80* left
+.irow acl "ACL interpretation"
+.irow auth "authenticators"
+.irow deliver "general delivery logic"
+.irow dns "DNS lookups (see also resolver)"
+.irow dnsbl "DNS black list (aka RBL) code"
+.irow exec "arguments for &[execv()]& calls"
+.irow expand "detailed debugging for string expansions"
+.irow filter "filter handling"
+.irow hints_lookup "hints data lookups"
+.irow host_lookup "all types of name-to-IP address handling"
+.irow ident "ident lookup"
+.irow interface "lists of local interfaces"
+.irow lists "matching things in lists"
+.irow load "system load checks"
+.irow local_scan "can be used by &[local_scan()]& (see chapter &&&
+ &<<CHAPlocalscan>>&)"
+.irow lookup "general lookup code and all lookups"
+.irow memory "memory handling"
+.irow noutf8 "modifier: avoid UTF-8 line-drawing"
+.irow pid "modifier: add pid to debug output lines"
+.irow process_info "setting info for the process log"
+.irow queue_run "queue runs"
+.irow receive "general message reception logic"
+.irow resolver "turn on the DNS resolver's debugging output"
+.irow retry "retry handling"
+.irow rewrite "address rewriting""
+.irow route "address routing"
+.irow timestamp "modifier: add timestamp to debug output lines"
+.irow tls "TLS logic"
+.irow transport "transports"
+.irow uid "changes of uid/gid and looking up uid/gid"
+.irow verify "address verification logic"
+.irow all "almost all of the above (see below), and also &%-v%&"
+.endtable
The &`all`& option excludes &`memory`& when used as &`+all`&, but includes it
for &`-all`&. The reason for this is that &`+all`& is something that people
tend to use when generating debug output for Exim maintainers. If &`+memory`&
subprocesses that the daemon creates. Thus, it is useful for monitoring the
behaviour of the daemon without creating as much output as full debugging does.
-.vitem &%-dropcr%&
-.oindex "&%-dropcr%&"
+.cmdopt -dropcr
This is an obsolete option that is now a no-op. It used to affect the way Exim
handled CR and LF characters in incoming messages. What happens now is
described in section &<<SECTlineendings>>&.
-.vitem &%-E%&
-.oindex "&%-E%&"
+.cmdopt -E
.cindex "bounce message" "generating"
This option specifies that an incoming message is a locally-generated delivery
failure report. It is used internally by Exim when handling delivery failures
example, the &%vacation%& program uses &%-eq%&. Exim treats all options of the
form &%-e%&&'x'& as synonymous with the corresponding &%-oe%&&'x'& options.
-.vitem &%-F%&&~<&'string'&>
-.oindex "&%-F%&"
+.cmdopt -F <&'string'&>
.cindex "sender" "name"
.cindex "name" "of sender"
This option sets the sender's full name for use when a locally-generated
their &'gecos'& entries, no security considerations are involved. White space
between &%-F%& and the <&'string'&> is optional.
-.vitem &%-f%&&~<&'address'&>
-.oindex "&%-f%&"
+.cmdopt -f <&'address'&>
.cindex "sender" "address"
.cindex "address" "sender"
.cindex "trusted users"
&"From&~"& line in the message &-- see the description of &%-bm%& above &-- but
if &%-f%& is also present, it overrides &"From&~"&.
-.vitem &%-G%&
-.oindex "&%-G%&"
+.cmdopt -G
.cindex "submission fixups, suppressing (command-line)"
This option is equivalent to an ACL applying:
.code
As this affects audit information, the caller must be a trusted user to use
this option.
-.vitem &%-h%&&~<&'number'&>
-.oindex "&%-h%&"
+.cmdopt -h <&'number'&>
.cindex "Sendmail compatibility" "&%-h%& option ignored"
This option is accepted for compatibility with Sendmail, but has no effect. (In
Sendmail it overrides the &"hop count"& obtained by counting &'Received:'&
headers.)
-.vitem &%-i%&
-.oindex "&%-i%&"
+.cmdopt -i
.cindex "Solaris" "&'mail'& command"
.cindex "dot" "in incoming non-SMTP message"
This option, which has the same effect as &%-oi%&, specifies that a dot on a
p. 1M-529), and therefore a &%-oi%& command line option, which both are used
by its &'mailx'& command.
-.vitem &%-L%&&~<&'tag'&>
-.oindex "&%-L%&"
+.cmdopt -L <&'tag'&>
.cindex "syslog" "process name; set with flag"
This option is equivalent to setting &%syslog_processname%& in the config
file and setting &%log_file_path%& to &`syslog`&.
The tag should not be longer than 32 characters.
-.vitem &%-M%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
-.oindex "&%-M%&"
+.cmdopt -M <&'message&~id'&>&~<&'message&~id'&>&~...
.cindex "forcing delivery"
.cindex "delivery" "forcing attempt"
.cindex "frozen messages" "forcing delivery"
produced unless there is a serious error. If you want to see what is happening,
use the &%-v%& option as well, or inspect Exim's main log.
-.vitem &%-Mar%&&~<&'message&~id'&>&~<&'address'&>&~<&'address'&>&~...
-.oindex "&%-Mar%&"
+.cmdopt -Mar <&'message&~id'&>&~<&'address'&>&~<&'address'&>&~...
.cindex "message" "adding recipients"
.cindex "recipient" "adding"
This option requests Exim to add the addresses to the list of recipients of the
given in chapter &<<CHAPSMTP>>&. This must be the final option, and the caller
must be root or the Exim user in order to use it.
-.vitem &%-MCA%&
-.oindex "&%-MCA%&"
+.cmdopt -MCA
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that the
connection to the remote host has been authenticated.
-.vitem &%-MCD%&
-.oindex "&%-MCD%&"
+.cmdopt -MCD
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that the
remote host supports the ESMTP &_DSN_& extension.
-.vitem &%-MCd%&
-.oindex "&%-MCd%&"
+.cmdopt -MCd
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-d%& option
to pass on an information string on the purpose of the process.
-.vitem &%-MCG%&&~<&'queue&~name'&>
-.oindex "&%-MCG%&"
+.cmdopt -MCG <&'queue&~name'&>
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that an
alternate queue is used, named by the following argument.
-.vitem &%-MCK%&
-.oindex "&%-MCK%&"
+.cmdopt -MCK
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that a
remote host supports the ESMTP &_CHUNKING_& extension.
-.vitem &%-MCL%&
-.oindex "&%-MCL%&"
+.cmdopt -MCL
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that the server to
which Exim is connected advertised limits on numbers of mails, recipients or
recipient domains.
The limits are given by the following three arguments.
-.vitem &%-MCP%&
-.oindex "&%-MCP%&"
+.cmdopt -MCP
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that the server to
which Exim is connected supports pipelining.
-.vitem &%-MCp%&
-.oindex "&%-MCp%&"
+.cmdopt -MCp
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option. It signifies that the connection
t a remote server is via a SOCKS proxy, using addresses and ports given by
the following four arguments.
-.vitem &%-MCQ%&&~<&'process&~id'&>&~<&'pipe&~fd'&>
-.oindex "&%-MCQ%&"
+.cmdopt -MCQ <&'process&~id'&>&~<&'pipe&~fd'&>
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option when the original delivery was
started by a queue runner. It passes on the process id of the queue runner,
signals the final completion of the sequence of processes that are passing
messages through the same SMTP connection.
-.vitem &%-MCq%&&~<&'recipient&~address'&>&~<&'size'&>
-.oindex "&%-MCq%&"
+.cmdopt -MCq <&'recipient&~address'&>&~<&'size'&>
This option is not intended for use by external callers. It is used internally
by Exim to implement quota checking for local users.
-.vitem &%-MCS%&
-.oindex "&%-MCS%&"
+.cmdopt -MCS
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
ESMTP SIZE option should be used on messages delivered down the existing
connection.
-.vitem &%-MCT%&
-.oindex "&%-MCT%&"
+.cmdopt -MCT
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
host to which Exim is connected supports TLS encryption.
The argument gives the SNI string.
The "r" variant indicates a DANE-verified connection.
-.vitem &%-MCt%&&~<&'IP&~address'&>&~<&'port'&>&~<&'cipher'&>
-.oindex "&%-MCt%&"
+.cmdopt -MCt <&'IP&~address'&>&~<&'port'&>&~<&'cipher'&>
This option is not intended for use by external callers. It is used internally
by Exim in conjunction with the &%-MC%& option, and passes on the fact that the
connection is being proxied by a parent process for handling TLS encryption.
The arguments give the local address and port being proxied, and the TLS cipher.
-.vitem &%-Mc%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
-.oindex "&%-Mc%&"
+.cmdopt -Mc <&'message&~id'&>&~<&'message&~id'&>&~...
.cindex "hints database" "not overridden by &%-Mc%&"
.cindex "delivery" "manually started &-- not forced"
This option requests Exim to run a delivery attempt on each message, in turn,
&%-q%& with a message id argument. A distinction between queue run deliveries
and other deliveries is made in one or two places.
-.vitem &%-Mes%&&~<&'message&~id'&>&~<&'address'&>
-.oindex "&%-Mes%&"
+.cmdopt -Mes <&'message&~id'&>&~<&'address'&>
.cindex "message" "changing sender"
.cindex "sender" "changing"
This option requests Exim to change the sender address in the message to the
is active (in the middle of a delivery attempt), its status is not altered.
This option can be used only by an admin user.
-.vitem &%-Mf%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
-.oindex "&%-Mf%&"
+.cmdopt -Mf <&'message&~id'&>&~<&'message&~id'&>&~...
.cindex "freezing messages"
.cindex "message" "manually freezing"
This option requests Exim to mark each listed message as &"frozen"&. This
attempt), their status is not altered. This option can be used only by an admin
user.
-.vitem &%-Mg%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
-.oindex "&%-Mg%&"
+.cmdopt -Mg <&'message&~id'&>&~<&'message&~id'&>&~...
.cindex "giving up on messages"
.cindex "message" "abandoning delivery attempts"
.cindex "delivery" "abandoning further attempts"
Bounce messages are just discarded. This option can be used only by an admin
user.
-.vitem &%-MG%&&~<&'queue&~name'&>&~<&'message&~id'&>&~<&'message&~id'&>&~...
-.oindex "&%-MG%&"
+.cmdopt -MG <&'queue&~name'&>&~<&'message&~id'&>&~<&'message&~id'&>&~...
.cindex queue named
.cindex "named queues" "moving messages"
.cindex "queue" "moving messages"
If the messages are not currently located in the default queue,
a &%-qG<name>%& option will be required to define the source queue.
-.vitem &%-Mmad%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
-.oindex "&%-Mmad%&"
+.cmdopt -Mmad <&'message&~id'&>&~<&'message&~id'&>&~...
.cindex "delivery" "cancelling all"
This option requests Exim to mark all the recipient addresses in the messages
as already delivered (&"mad"& for &"mark all delivered"&). However, if any
message is active (in the middle of a delivery attempt), its status is not
altered. This option can be used only by an admin user.
-.vitem &%-Mmd%&&~<&'message&~id'&>&~<&'address'&>&~<&'address'&>&~...
-.oindex "&%-Mmd%&"
+.cmdopt -Mmd <&'message&~id'&>&~<&'address'&>&~<&'address'&>&~...
.cindex "delivery" "cancelling by address"
.cindex "recipient" "removing"
.cindex "removing recipients"
(in the middle of a delivery attempt), its status is not altered. This option
can be used only by an admin user.
-.vitem &%-Mrm%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
-.oindex "&%-Mrm%&"
+.cmdopt -Mrm <&'message&~id'&>&~<&'message&~id'&>&~...
.cindex "removing messages"
.cindex "abandoning mail"
.cindex "message" "manually discarding"
. a bounce message.
. .wen
-.vitem &%-Mset%&&~<&'message&~id'&>
-.oindex "&%-Mset%&"
+.cmdopt -Mset <&'message&~id'&>
.cindex "testing" "string expansion"
.cindex "expansion" "testing"
This option is useful only in conjunction with &%-be%& (that is, when testing
make use of these variables. However, this option can be used only by an admin
user. See also &%-bem%&.
-.vitem &%-Mt%&&~<&'message&~id'&>&~<&'message&~id'&>&~...
-.oindex "&%-Mt%&"
+.cmdopt -Mt <&'message&~id'&>&~<&'message&~id'&>&~...
.cindex "thawing messages"
.cindex "unfreezing messages"
.cindex "frozen messages" "thawing"
messages are active, their status is not altered. This option can be used only
by an admin user.
-.vitem &%-Mvb%&&~<&'message&~id'&>
-.oindex "&%-Mvb%&"
+.cmdopt -Mvb <&'message&~id'&>
.cindex "listing" "message body"
.cindex "message" "listing body of"
This option causes the contents of the message body (-D) spool file to be
written to the standard output. This option can be used only by an admin user.
-.vitem &%-Mvc%&&~<&'message&~id'&>
-.oindex "&%-Mvc%&"
+.cmdopt -Mvc <&'message&~id'&>
.cindex "message" "listing in RFC 2822 format"
.cindex "listing" "message in RFC 2822 format"
This option causes a copy of the complete message (header lines plus body) to
be written to the standard output in RFC 2822 format. This option can be used
only by an admin user.
-.vitem &%-Mvh%&&~<&'message&~id'&>
-.oindex "&%-Mvh%&"
+.cmdopt -Mvh <&'message&~id'&>
.cindex "listing" "message headers"
.cindex "header lines" "listing"
.cindex "message" "listing header lines"
This option causes the contents of the message headers (-H) spool file to be
written to the standard output. This option can be used only by an admin user.
-.vitem &%-Mvl%&&~<&'message&~id'&>
-.oindex "&%-Mvl%&"
+.cmdopt -Mvl <&'message&~id'&>
.cindex "listing" "message log"
.cindex "message" "listing message log"
This option causes the contents of the message log spool file to be written to
the standard output. This option can be used only by an admin user.
-.vitem &%-m%&
-.oindex "&%-m%&"
+.cmdopt -m
This is a synonym for &%-om%& that is accepted by Sendmail
(&url(https://docs.oracle.com/cd/E19457-01/801-6680-1M/801-6680-1M.pdf)
p. 1M-258), so Exim treats it that way too.
-.vitem &%-N%&
-.oindex "&%-N%&"
+.cmdopt -N
.cindex "debugging" "&%-N%& option"
.cindex "debugging" "suppressing delivery"
This is a debugging option that inhibits delivery of a message at the transport
the message, and applies to any subsequent delivery attempts that may happen
for that message.
-.vitem &%-n%&
-.oindex "&%-n%&"
+.cmdopt -n
This option is interpreted by Sendmail to mean &"no aliasing"&.
For normal modes of operation, it is ignored by Exim.
When combined with &%-bP%& it makes the output more terse (suppresses
option names, environment values and config pretty printing).
-.vitem &%-O%&&~<&'data'&>
-.oindex "&%-O%&"
+.cmdopt -O <&'data'&>
This option is interpreted by Sendmail to mean &`set option`&. It is ignored by
Exim.
-.vitem &%-oA%&&~<&'file&~name'&>
-.oindex "&%-oA%&"
+.cmdopt -oA <&'file&~name'&>
.cindex "Sendmail compatibility" "&%-oA%& option"
This option is used by Sendmail in conjunction with &%-bi%& to specify an
alternative alias filename. Exim handles &%-bi%& differently; see the
description above.
-.vitem &%-oB%&&~<&'n'&>
-.oindex "&%-oB%&"
+.cmdopt -oB <&'n'&>
.cindex "SMTP" "passed connection"
.cindex "SMTP" "multiple deliveries"
.cindex "multiple SMTP deliveries"
be delivered down one SMTP connection, overriding the value set in any &(smtp)&
transport. If <&'n'&> is omitted, the limit is set to 1.
-.vitem &%-odb%&
-.oindex "&%-odb%&"
+.cmdopt -odb
.cindex "background delivery"
.cindex "delivery" "in the background"
This option applies to all modes in which Exim accepts incoming messages,
overrides it if &%queue_only_override%& is set true, which is the default
setting. If &%queue_only_override%& is set false, &%-odb%& has no effect.
-.vitem &%-odf%&
-.oindex "&%-odf%&"
+.cmdopt -odf
.cindex "foreground delivery"
.cindex "delivery" "in the foreground"
This option requests &"foreground"& (synchronous) delivery when Exim has
restricted configuration that never queues messages.
-.vitem &%-odi%&
-.oindex "&%-odi%&"
+.cmdopt -odi
This option is synonymous with &%-odf%&. It is provided for compatibility with
Sendmail.
-.vitem &%-odq%&
-.oindex "&%-odq%&"
+.cmdopt -odq
.cindex "non-immediate delivery"
.cindex "delivery" "suppressing immediate"
.cindex "queueing incoming messages"
conditions. This option overrides all of them and also &%-odqs%&. It always
forces queueing.
-.vitem &%-odqs%&
-.oindex "&%-odqs%&"
+.cmdopt -odqs
.cindex "SMTP" "delaying delivery"
.cindex "first pass routing"
This option is a hybrid between &%-odb%&/&%-odi%& and &%-odq%&.
configuration option has the same effect for specific domains. See also the
&%-qq%& option.
-.vitem &%-oee%&
-.oindex "&%-oee%&"
+.cmdopt -oee
.cindex "error" "reporting"
If an error is detected while a non-SMTP message is being received (for
example, a malformed address), the error is reported to the sender in a mail
is that the original message has no recipients, or 1 for any other error.
This is the default &%-oe%&&'x'& option if Exim is called as &'rmail'&.
-.vitem &%-oem%&
-.oindex "&%-oem%&"
+.cmdopt -oem
.cindex "error" "reporting"
.cindex "return code" "for &%-oem%&"
This is the same as &%-oee%&, except that Exim always exits with a non-zero
return code, whether or not the error message was successfully sent.
This is the default &%-oe%&&'x'& option, unless Exim is called as &'rmail'&.
-.vitem &%-oep%&
-.oindex "&%-oep%&"
+.cmdopt -oep
.cindex "error" "reporting"
If an error is detected while a non-SMTP message is being received, the
error is reported by writing a message to the standard error file (stderr).
.cindex "return code" "for &%-oep%&"
The return code is 1 for all errors.
-.vitem &%-oeq%&
-.oindex "&%-oeq%&"
+.cmdopt -oeq
.cindex "error" "reporting"
This option is supported for compatibility with Sendmail, but has the same
effect as &%-oep%&.
-.vitem &%-oew%&
-.oindex "&%-oew%&"
+.cmdopt -oew
.cindex "error" "reporting"
This option is supported for compatibility with Sendmail, but has the same
effect as &%-oem%&.
-.vitem &%-oi%&
-.oindex "&%-oi%&"
+.cmdopt -oi
.cindex "dot" "in incoming non-SMTP message"
This option, which has the same effect as &%-i%&, specifies that a dot on a
line by itself should not terminate an incoming, non-SMTP message. Otherwise, a
lines that start with a dot. This option is set by default if Exim is called as
&'rmail'&. See also &%-ti%&.
-.vitem &%-oitrue%&
-.oindex "&%-oitrue%&"
+.cmdopt -oitrue
This option is treated as synonymous with &%-oi%&.
-.vitem &%-oMa%&&~<&'host&~address'&>
-.oindex "&%-oMa%&"
+.cmdopt -oMa <&'host&~address'&>
.cindex "sender" "host address, specifying for local message"
A number of options starting with &%-oM%& can be used to set values associated
with remote hosts on locally-submitted messages (that is, messages not received
are present on the command line, the sender host IP address is taken from
whichever one is last.
-.vitem &%-oMaa%&&~<&'name'&>
-.oindex "&%-oMaa%&"
+.cmdopt -oMaa <&'name'&>
.cindex "authentication" "name, specifying for local message"
See &%-oMa%& above for general remarks about the &%-oM%& options. The &%-oMaa%&
option sets the value of &$sender_host_authenticated$& (the authenticator
This option can be used with &%-bh%& and &%-bs%& to set up an
authenticated SMTP session without actually using the SMTP AUTH command.
-.vitem &%-oMai%&&~<&'string'&>
-.oindex "&%-oMai%&"
+.cmdopt -oMai <&'string'&>
.cindex "authentication" "id, specifying for local message"
See &%-oMa%& above for general remarks about the &%-oM%& options. The &%-oMai%&
option sets the value of &$authenticated_id$& (the id that was authenticated).
where there is no default) for messages from local sources. See chapter
&<<CHAPSMTPAUTH>>& for a discussion of authenticated ids.
-.vitem &%-oMas%&&~<&'address'&>
-.oindex "&%-oMas%&"
+.cmdopt -oMas <&'address'&>
.cindex "authentication" "sender, specifying for local message"
See &%-oMa%& above for general remarks about the &%-oM%& options. The &%-oMas%&
option sets the authenticated sender value in &$authenticated_sender$&. It
specified on a MAIL command overrides this value. See chapter
&<<CHAPSMTPAUTH>>& for a discussion of authenticated senders.
-.vitem &%-oMi%&&~<&'interface&~address'&>
-.oindex "&%-oMi%&"
+.cmdopt -oMi <&'interface&~address'&>
.cindex "interface" "address, specifying for local message"
See &%-oMa%& above for general remarks about the &%-oM%& options. The &%-oMi%&
option sets the IP interface address value. A port number may be included,
using the same syntax as for &%-oMa%&. The interface address is placed in
&$received_ip_address$& and the port number, if present, in &$received_port$&.
-.vitem &%-oMm%&&~<&'message&~reference'&>
-.oindex "&%-oMm%&"
+.cmdopt -oMm <&'message&~reference'&>
.cindex "message reference" "message reference, specifying for local message"
See &%-oMa%& above for general remarks about the &%-oM%& options. The &%-oMm%&
option sets the message reference, e.g. message-id, and is logged during
The message reference is the message-id of the original message for which Exim
is sending the bounce.
-.vitem &%-oMr%&&~<&'protocol&~name'&>
-.oindex "&%-oMr%&"
+.cmdopt -oMr <&'protocol&~name'&>
.cindex "protocol, specifying for local message"
.vindex "&$received_protocol$&"
See &%-oMa%& above for general remarks about the &%-oM%& options. The &%-oMr%&
one of those same names. For &%-bS%& (batched SMTP) however, the protocol can
be set by &%-oMr%&. Repeated use of this option is not supported.
-.vitem &%-oMs%&&~<&'host&~name'&>
-.oindex "&%-oMs%&"
+.cmdopt -oMs <&'host&~name'&>
.cindex "sender" "host name, specifying for local message"
See &%-oMa%& above for general remarks about the &%-oM%& options. The &%-oMs%&
option sets the sender host name in &$sender_host_name$&. When this option is
present, Exim does not attempt to look up a host name from an IP address; it
uses the name it is given.
-.vitem &%-oMt%&&~<&'ident&~string'&>
-.oindex "&%-oMt%&"
+.cmdopt -oMt <&'ident&~string'&>
.cindex "sender" "ident string, specifying for local message"
See &%-oMa%& above for general remarks about the &%-oM%& options. The &%-oMt%&
option sets the sender ident value in &$sender_ident$&. The default setting for
local callers is the login id of the calling process, except when &%-bh%& is
used, when there is no default.
-.vitem &%-om%&
-.oindex "&%-om%&"
+.cmdopt -om
.cindex "Sendmail compatibility" "&%-om%& option ignored"
In Sendmail, this option means &"me too"&, indicating that the sender of a
message should receive a copy of the message if the sender appears in an alias
expansion. Exim always does this, so the option does nothing.
-.vitem &%-oo%&
-.oindex "&%-oo%&"
+.cmdopt -oo
.cindex "Sendmail compatibility" "&%-oo%& option ignored"
This option is ignored. In Sendmail it specifies &"old style headers"&,
whatever that means.
-.vitem &%-oP%&&~<&'path'&>
-.oindex "&%-oP%&"
+.cmdopt -oP <&'path'&>
.cindex "pid (process id)" "of daemon"
.cindex "daemon" "process id (pid)"
This option is useful only in conjunction with &%-bd%& or &%-q%& with a time
without &%-bd%&, this is the only way of causing Exim to write a pid file,
because in those cases, the normal pid file is not used.
-.vitem &%-oPX%&
-.oindex "&%-oPX%&"
+.cmdopt -oPX
.cindex "pid (process id)" "of daemon"
.cindex "daemon" "process id (pid)"
This option is not intended for general use.
combination with &%-oP%&&~<&'path'&>.
It causes the pid file to be removed.
-.vitem &%-or%&&~<&'time'&>
-.oindex "&%-or%&"
+.cmdopt -or <&'time'&>
.cindex "timeout" "for non-SMTP input"
This option sets a timeout value for incoming non-SMTP messages. If it is not
set, Exim will wait forever for the standard input. The value can also be set
by the &%receive_timeout%& option. The format used for specifying times is
described in section &<<SECTtimeformat>>&.
-.vitem &%-os%&&~<&'time'&>
-.oindex "&%-os%&"
+.cmdopt -os <&'time'&>
.cindex "timeout" "for SMTP input"
.cindex "SMTP" "input timeout"
This option sets a timeout value for incoming SMTP messages. The timeout
the &%smtp_receive_timeout%& option; it defaults to 5 minutes. The format used
for specifying times is described in section &<<SECTtimeformat>>&.
-.vitem &%-ov%&
-.oindex "&%-ov%&"
+.cmdopt -ov
This option has exactly the same effect as &%-v%&.
-.vitem &%-oX%&&~<&'number&~or&~string'&>
-.oindex "&%-oX%&"
+.cmdopt -oX <&'number&~or&~string'&>
.cindex "TCP/IP" "setting listening ports"
.cindex "TCP/IP" "setting listening interfaces"
.cindex "port" "receiving TCP/IP"
in chapter &<<CHAPinterfaces>>&. When &%-oX%& is used to start a daemon, no pid
file is written unless &%-oP%& is also present to specify a pid filename.
-.vitem &%-oY%&
-.oindex &%-oY%&
+.cmdopt -oY
.cindex "daemon notifier socket"
This option controls the creation of an inter-process communications endpoint
by the Exim daemon.
obtaining a current queue size
.endlist
-.vitem &%-pd%&
-.oindex "&%-pd%&"
+.cmdopt -pd
.cindex "Perl" "starting the interpreter"
This option applies when an embedded Perl interpreter is linked with Exim (see
chapter &<<CHAPperl>>&). It overrides the setting of the &%perl_at_start%&
option, forcing the starting of the interpreter to be delayed until it is
needed.
-.vitem &%-ps%&
-.oindex "&%-ps%&"
+.cmdopt -ps
.cindex "Perl" "starting the interpreter"
This option applies when an embedded Perl interpreter is linked with Exim (see
chapter &<<CHAPperl>>&). It overrides the setting of the &%perl_at_start%&
or &`s`& using this option (but that does not seem a real limitation).
Repeated use of this option is not supported.
-.vitem &%-q%&
-.oindex "&%-q%&"
+.cmdopt -q
.cindex "queue runner" "starting manually"
This option is normally restricted to admin users. However, there is a
configuration option called &%prod_requires_admin%& which can be set false to
effect is to run Exim with the &%-R%& option, but it can be configured to run
an arbitrary command instead.
-.vitem &%-r%&
-.oindex "&%-r%&"
+.cmdopt -r
This is a documented (for Sendmail) obsolete alternative name for &%-f%&.
.vitem &%-S%&<&'rsflags'&>&~<&'string'&>
conditions must be met for a message to be selected. If either of the options
has &'f'& or &'ff'& in its flags, the associated action is taken.
-.vitem &%-Tqt%&&~<&'times'&>
-.oindex "&%-Tqt%&"
+.cmdopt -Tqt <&'times'&>
This is an option that is exclusively for use by the Exim testing suite. It is not
recognized when Exim is run normally. It allows for the setting up of explicit
&"queue times"& so that various warning/retry features can be tested.
-.vitem &%-t%&
-.oindex "&%-t%&"
+.cmdopt -t
.cindex "recipient" "extracting from header lines"
.chindex Bcc:
.chindex Cc:
once, it is common for the original set of &%Resent-%& headers to be renamed as
&%X-Resent-%& when a new set is added. This removes any possible ambiguity.
-.vitem &%-ti%&
-.oindex "&%-ti%&"
+.cmdopt -ti
This option is exactly equivalent to &%-t%& &%-i%&. It is provided for
compatibility with Sendmail.
-.vitem &%-tls-on-connect%&
-.oindex "&%-tls-on-connect%&"
+.cmdopt -tls-on-connect
.cindex "TLS" "use without STARTTLS"
.cindex "TLS" "automatic start"
This option is available when Exim is compiled with TLS support. It forces all
&<<CHAPTLS>>& for further details.
-.vitem &%-U%&
-.oindex "&%-U%&"
+.cmdopt -U
.cindex "Sendmail compatibility" "&%-U%& option ignored"
Sendmail uses this option for &"initial message submission"&, and its
documentation states that in future releases, it may complain about
syntactically invalid messages rather than fixing them when this flag is not
set. Exim ignores this option.
-.vitem &%-v%&
-.oindex "&%-v%&"
+.cmdopt -v
This option causes Exim to write information to the standard error stream,
describing what it is doing. In particular, it shows the log lines for
receiving and delivering a message, and if an SMTP connection is made, the SMTP
selectors are shown with each log line. If none are shown, the logging is
unconditional.
-.vitem &%-x%&
-.oindex "&%-x%&"
+.cmdopt -x
AIX uses &%-x%& for a private purpose (&"mail from a local mail program has
National Language Support extended characters in the body of the mail item"&).
It sets &%-x%& when calling the MTA from its &%mail%& command. Exim ignores
this option.
-.vitem &%-X%&&~<&'logfile'&>
-.oindex "&%-X%&"
+.cmdopt -X <&'logfile'&>
This option is interpreted by Sendmail to cause debug information to be sent
to the named file. It is ignored by Exim.
-.vitem &%-z%&&~<&'log-line'&>
-.oindex "&%-z%&"
+.cmdopt -z <&'log-line'&>
This option writes its argument to Exim's logfile.
Use is restricted to administrators; the intent is for operational notes.
Quotes should be used to maintain a multi-word item as a single argument,
lookup. Lookups of this type are conditional expansion items. Different results
can be defined for the cases of lookup success and failure. See chapter
&<<CHAPexpand>>&, where string expansions are described in detail.
-The key for the lookup is &*specified*& as part of the string expansion.
+The key for the lookup is &*specified*& as part of the string to be expanded.
.next
Lists of domains, hosts, and email addresses can contain lookup requests as a
way of avoiding excessively long linear lists. In this case, the data that is
returned by the lookup is often (but not always) discarded; whether the lookup
succeeds or fails is what really counts. These kinds of list are described in
chapter &<<CHAPdomhosaddlists>>&.
-The key for the lookup is &*implicit*&,
-given by the context in which the list is expanded.
+Depending on the lookup type (see below)
+the key for the lookup may need to be &*specified*& as above
+or may be &*implicit*&,
+given by the context in which the list is being checked.
.endlist
String expansions, lists, and lookups interact with each other in such a way
domains = ${lookup{$sender_host_address}lsearch{/some/file}}
domains = lsearch;/some/file
.endd
+.ilist
The first uses a string expansion, the result of which must be a domain list.
-.new
The key for an expansion-style lookup must be given explicitly.
-.wen
No strings have been specified for a successful or a failing lookup; the
defaults in this case are the looked-up data and an empty string, respectively.
The expansion takes place before the string is processed as a list, and the
When the lookup succeeds, the result of the expansion is a list of domains (and
possibly other types of item that are allowed in domain lists).
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using a lookup expansion"
The result of the expansion is not tainted.
+.next
In the second example, the lookup is a single item in a domain list. It causes
Exim to use a lookup to see if the domain that is being processed can be found
in the file.
Any data that follows the keys is not relevant when checking that the domain
matches the list item.
-.new
The key for a list-style lookup is implicit, from the lookup context, if
the lookup is a single-key type (see below).
-For query-style lookup types the key must be given explicitly.
-.wen
+For query-style lookup types the query must be given explicitly.
+.endlist
It is possible, though no doubt confusing, to use both kinds of lookup at once.
Consider a file containing lines like this:
The file string may not be tainted.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using a single-key lookup"
All single-key lookups support the option &"ret=key"&.
If this is given and the lookup
(either underlying implementation or cached value)
returns data, the result is replaced with a non-tainted
version of the lookup key.
-.cindex "tainted data" "de-tainting"
+
.next
.cindex "query-style lookup" "definition of"
The &'query-style'& type accepts a generalized database query. No particular
key value is assumed by Exim for query-style lookups. You can use whichever
Exim variables you need to construct the database query.
.cindex "tainted data" "quoting for lookups"
-.new
If tainted data is used in the query then it should be quuted by
using the &*${quote_*&<&'lookup-type'&>&*:*&<&'string'&>&*}*& expansion operator
appropriate for the lookup.
-.wen
.endlist
The code for each lookup type is in a separate source file that is included in
.cindex "single-key lookup" "list of types"
The following single-key lookup types are implemented:
-.ilist
+.subsection cdb
.cindex "cdb" "description of"
.cindex "lookup" "cdb"
.cindex "binary zero" "in lookup key"
-&(cdb)&: The given file is searched as a Constant DataBase file, using the key
+The given file is searched as a Constant DataBase file, using the key
string without a terminating binary zero. The cdb format is designed for
indexed files that are read frequently and never updated, except by total
re-creation. As such, it is particularly suitable for large files containing
because the code for reading cdb files is included directly in Exim itself.
However, no means of building or testing cdb files is provided with Exim, so
you need to obtain a cdb distribution in order to do this.
-.next
+
+.subsection dbm
.cindex "DBM" "lookup type"
.cindex "lookup" "dbm"
.cindex "binary zero" "in lookup key"
-&(dbm)&: Calls to DBM library functions are used to extract data from the given
+Calls to DBM library functions are used to extract data from the given
DBM file by looking up the record with the given key. A terminating binary
zero is included in the key that is passed to the DBM library. See section
&<<SECTdb>>& for a discussion of DBM libraries.
the DB_UNKNOWN option. This enables it to handle any of the types of database
that the library supports, and can be useful for accessing DBM files created by
other applications. (For earlier DB versions, DB_HASH is always used.)
-.next
+
+.subsection dbmjz
.cindex "lookup" "dbmjz"
.cindex "lookup" "dbm &-- embedded NULs"
.cindex "sasldb2"
.cindex "dbmjz lookup type"
-&(dbmjz)&: This is the same as &(dbm)&, except that the lookup key is
+This is the same as &(dbm)&, except that the lookup key is
interpreted as an Exim list; the elements of the list are joined together with
ASCII NUL characters to form the lookup key. An example usage would be to
authenticate incoming SMTP calls using the passwords from Cyrus SASL's
&_/etc/sasldb2_& file with the &(gsasl)& authenticator or Exim's own
&(cram_md5)& authenticator.
-.next
+
+.subsection dbmnz
.cindex "lookup" "dbmnz"
.cindex "lookup" "dbm &-- terminating zero"
.cindex "binary zero" "in lookup key"
.cindex "Courier"
.cindex "&_/etc/userdbshadow.dat_&"
.cindex "dbmnz lookup type"
-&(dbmnz)&: This is the same as &(dbm)&, except that a terminating binary zero
+This is the same as &(dbm)&, except that a terminating binary zero
is not included in the key that is passed to the DBM library. You may need this
if you want to look up data in files that are created by or shared with some
other application that does not use terminating zeros. For example, you need to
calls using the passwords from Courier's &_/etc/userdbshadow.dat_& file. Exim's
utility program for creating DBM files (&'exim_dbmbuild'&) includes the zeros
by default, but has an option to omit them (see section &<<SECTdbmbuild>>&).
-.next
+
+.subsection dsearch
.cindex "lookup" "dsearch"
.cindex "dsearch lookup type"
-&(dsearch)&: The given file must be an
-absolute
-directory path; this is searched for an entry
+The given file must be an absolute directory path; this is searched for an entry
whose name is the key by calling the &[lstat()]& function.
-The key may not
-contain any forward slash characters.
+The key may not contain any forward slash characters.
If &[lstat()]& succeeds then so does the lookup.
.cindex "tainted data" "dsearch result"
The result is regarded as untainted.
An example of how this
lookup can be used to support virtual domains is given in section
&<<SECTvirtualdomains>>&.
-.next
+
+.subsection iplsearch
.cindex "lookup" "iplsearch"
.cindex "iplsearch lookup type"
-&(iplsearch)&: The given file is a text file containing keys and data. A key is
+The given file is a text file containing keys and data. A key is
terminated by a colon or white space or the end of the line. The keys in the
file must be IP addresses, or IP addresses with CIDR masks. Keys that involve
IPv6 addresses must be enclosed in quotes to prevent the first internal colon
rather than omitting the key portion.
Note however that the key portion will have been de-quoted.
-.next
+.subsection json
.cindex lookup json
.cindex json "lookup type"
.cindex JSON expansions
-&(json)&: The given file is a text file with a JSON structure.
+The given file is a text file with a JSON structure.
An element of the structure is extracted, defined by the search key.
The key is a list of subelement selectors
(colon-separated by default but changeable in the usual way)
For elements of type string, the returned value is de-quoted.
-.next
+.subsection lmdb
.cindex LMDB
.cindex lookup lmdb
.cindex database lmdb
-&(lmdb)&: The given file is an LMDB database.
+The given file is an LMDB database.
LMDB is a memory-mapped key-value store,
with API modeled loosely on that of BerkeleyDB.
See &url(https://symas.com/products/lightning-memory-mapped-database/)
possibly using the &"mdb_load"& utility.
-.next
+.subsection lsearch
.cindex "linear search"
.cindex "lookup" "lsearch"
.cindex "lsearch lookup type"
.cindex "case sensitivity" "in lsearch lookup"
-&(lsearch)&: The given file is a text file that is searched linearly for a
+The given file is a text file that is searched linearly for a
line beginning with the search key, terminated by a colon or white space or the
end of the line. The search is case-insensitive; that is, upper and lower case
letters are treated as the same. The first occurrence of the key that is found
quoted keys (exactly as for unquoted keys). There is no special handling of
quotes for the data part of an &(lsearch)& line.
-.next
+.subsection nis
.cindex "NIS lookup type"
.cindex "lookup" "NIS"
.cindex "binary zero" "in lookup key"
-&(nis)&: The given file is the name of a NIS map, and a NIS lookup is done with
+The given file is the name of a NIS map, and a NIS lookup is done with
the given key, without a terminating binary zero. There is a variant called
&(nis0)& which does include the terminating binary zero in the key. This is
reportedly needed for Sun-style alias files. Exim does not recognize NIS
aliases; the full map names must be used.
-.next
+.subsection (n)wildlsearch
.cindex "wildlsearch lookup type"
.cindex "lookup" "wildlsearch"
.cindex "nwildlsearch lookup type"
file that are regular expressions can be made case-sensitive by the use of
&`(-i)`& within the pattern. The following forms of wildcard are recognized:
-. ==== As this is a nested list, any displays it contains must be indented
-. ==== as otherwise they are too far to the left.
-
.olist
The string may begin with an asterisk to mean &"ends with"&. For example:
.code
- *.a.b.c data for anything.a.b.c
- *fish data for anythingfish
+*.a.b.c data for anything.a.b.c
+*fish data for anythingfish
.endd
.next
The string may begin with a circumflex to indicate a regular expression. For
example, for &(wildlsearch)&:
.code
- ^\N\d+\.a\.b\N data for <digits>.a.b
+^\N\d+\.a\.b\N data for <digits>.a.b
.endd
Note the use of &`\N`& to disable expansion of the contents of the regular
expression. If you are using &(nwildlsearch)&, where the keys are not
string-expanded, the equivalent entry is:
.code
- ^\d+\.a\.b data for <digits>.a.b
+^\d+\.a\.b data for <digits>.a.b
.endd
The case-insensitive flag is set at the start of compiling the regular
expression, but it can be turned off by using &`(-i)`& at an appropriate point.
For example, to make the entire pattern case-sensitive:
.code
- ^(?-i)\d+\.a\.b data for <digits>.a.b
+^(?-i)\d+\.a\.b data for <digits>.a.b
.endd
If the regular expression contains white space or colon characters, you must
lookup name terminated by a semicolon, and followed by lookup data. For
example:
.code
- cdb;/some/file data for keys that match the file
+cdb;/some/file data for keys that match the file
.endd
The data that is obtained from the nested lookup is discarded.
.endlist olist
&((n)wildlsearch)& can &'not'& be turned into a DBM or cdb file, because those
lookup types support only literal keys.
-.next
+.subsection spf
.cindex "spf lookup type"
.cindex "lookup" "spf"
-&(spf)&: If Exim is built with SPF support, manual lookups can be done
+If Exim is built with SPF support, manual lookups can be done
(as opposed to the standard ACL condition method).
For details see section &<<SECSPF>>&.
-.endlist ilist
.section "Query-style lookup types" "SECTquerystylelookups"
The supported query-style lookup types are listed below. Further details about
many of them are given in later sections.
-.ilist
+.subsection dnsdb
.cindex "DNS" "as a lookup type"
.cindex "lookup" "DNS"
-&(dnsdb)&: This does a DNS search for one or more records whose domain names
+This does a DNS search for one or more records whose domain names
are given in the supplied query. The resulting data is the contents of the
records. See section &<<SECTdnsdb>>&.
-.next
+
+.subsection ibase
.cindex "InterBase lookup type"
.cindex "lookup" "InterBase"
-&(ibase)&: This does a lookup in an InterBase database.
-.next
+This does a lookup in an InterBase database.
+
+.subsection ldap
.cindex "LDAP" "lookup type"
.cindex "lookup" "LDAP"
-&(ldap)&: This does an LDAP lookup using a query in the form of a URL, and
+This does an LDAP lookup using a query in the form of a URL, and
returns attributes from a single entry. There is a variant called &(ldapm)&
that permits values from multiple entries to be returned. A third variant
called &(ldapdn)& returns the Distinguished Name of a single entry instead of
any attribute values. See section &<<SECTldap>>&.
-.next
+
+.subsection mysql
.cindex "MySQL" "lookup type"
.cindex "lookup" "MySQL"
-&(mysql)&: The format of the query is an SQL statement that is passed to a
+The format of the query is an SQL statement that is passed to a
MySQL database. See section &<<SECTsql>>&.
-.next
+
+.subsection nisplus
.cindex "NIS+ lookup type"
.cindex "lookup" "NIS+"
-&(nisplus)&: This does a NIS+ lookup using a query that can specify the name of
+This does a NIS+ lookup using a query that can specify the name of
the field to be returned. See section &<<SECTnisplus>>&.
-.next
+
+.subsection oracle
.cindex "Oracle" "lookup type"
.cindex "lookup" "Oracle"
-&(oracle)&: The format of the query is an SQL statement that is passed to an
+The format of the query is an SQL statement that is passed to an
Oracle database. See section &<<SECTsql>>&.
-.next
+
+.subsection passwd
.cindex "lookup" "passwd"
.cindex "passwd lookup type"
.cindex "&_/etc/passwd_&"
-&(passwd)& is a query-style lookup with queries that are just user names. The
+This is a query-style lookup with queries that are just user names. The
lookup calls &[getpwnam()]& to interrogate the system password data, and on
success, the result string is the same as you would get from an &(lsearch)&
lookup on a traditional &_/etc/passwd file_&, though with &`*`& for the
.code
*:42:42:King Rat:/home/kr:/bin/bash
.endd
-.next
+
+.subsection pgsql
.cindex "PostgreSQL lookup type"
.cindex "lookup" "PostgreSQL"
-&(pgsql)&: The format of the query is an SQL statement that is passed to a
+The format of the query is an SQL statement that is passed to a
PostgreSQL database. See section &<<SECTsql>>&.
-.next
+.subsection redis
.cindex "Redis lookup type"
.cindex lookup Redis
-&(redis)&: The format of the query is either a simple get or simple set,
+The format of the query is either a simple get or simple set,
passed to a Redis database. See section &<<SECTsql>>&.
-.next
+.subsection sqlite
.cindex "sqlite lookup type"
.cindex "lookup" "sqlite"
-&(sqlite)&: The format of the query is
+The format of the query is
an SQL statement that is passed to an SQLite database. See section &<<SECTsqlite>>&.
-.next
-&(testdb)&: This is a lookup type that is used for testing Exim. It is
+.subsection testdb
+This is a lookup type that is used for testing Exim. It is
not likely to be useful in normal operation.
-.next
+
+.subsection whoson
.cindex "whoson lookup type"
.cindex "lookup" "whoson"
-. --- still http:-only, 2018-09-07
-&(whoson)&: &'Whoson'& (&url(http://whoson.sourceforge.net)) is a protocol that
+&'Whoson'& (&url(http://whoson.sourceforge.net)) is a protocol that
allows a server to check whether a particular (dynamically allocated) IP
address is currently allocated to a known (trusted) user and, optionally, to
obtain the identity of the said user. For SMTP servers, &'Whoson'& was popular
the authenticated user, which is stored in the variable &$value$&. However, in
this example, the data in &$value$& is not used; the result of the lookup is
one of the fixed strings &"yes"& or &"no"&.
-.endlist
${lookup dnsdb{>:,; soa=a.b.example.com}}
.endd
-.section "Dnsdb lookup modifiers" "SECTdnsdb_mod"
+.subsection "Dnsdb lookup modifiers" SECTdnsdb_mod
.cindex "dnsdb modifiers"
.cindex "modifiers" "dnsdb"
.cindex "options" "dnsdb"
value of the set of returned DNS records.
-.section "Pseudo dnsdb record types" "SECID66"
+.subsection "Pseudo dnsdb record types" SECID66
.cindex "MX record" "in &(dnsdb)& lookup"
By default, both the preference value and the host name are returned for
each MX record, separated by a space. If you want only host names, you can use
.endd
-.section "Multiple dnsdb lookups" "SECID67"
+.subsection "Multiple dnsdb lookups" SECID67
In the previous sections, &(dnsdb)& lookups for a single domain are described.
However, you can specify a list of domains or IP addresses in a single
&(dnsdb)& lookup. The list is specified in the normal Exim way, with colon as
First we explain how LDAP queries are coded.
-.section "Format of LDAP queries" "SECTforldaque"
+.subsection "Format of LDAP queries" SECTforldaque
.cindex "LDAP" "query format"
An LDAP query takes the form of a URL as defined in RFC 2255. For example, in
the configuration of a &(redirect)& router one might have this setting:
&_exim.conf_&.
-.section "LDAP quoting" "SECID68"
+.subsection "LDAP quoting" SECID68
.cindex "LDAP" "quoting"
Two levels of quoting are required in LDAP queries, the first for LDAP itself
and the second because the LDAP query is represented as a URL. Furthermore,
authentication below.
-.section "LDAP connections" "SECID69"
+.subsection "LDAP connections" SECID69
.cindex "LDAP" "connections"
The connection to an LDAP server may either be over TCP/IP, or, when OpenLDAP
is in use, via a Unix domain socket. The example given above does not specify
-.section "LDAP authentication and control information" "SECID70"
+.subsection "LDAP authentication and control information" SECID70
.cindex "LDAP" "authentication"
The LDAP URL syntax provides no way of passing authentication and other control
information to the server. To make this possible, the URL in an LDAP query may
spaces. If a value contains spaces it must be enclosed in double quotes, and
when double quotes are used, backslash is interpreted in the usual way inside
them. The following names are recognized:
-.display
-&`DEREFERENCE`& set the dereferencing parameter
-&`NETTIME `& set a timeout for a network operation
-&`USER `& set the DN, for authenticating the LDAP bind
-&`PASS `& set the password, likewise
-&`REFERRALS `& set the referrals parameter
-&`SERVERS `& set alternate server list for this query only
-&`SIZE `& set the limit for the number of entries returned
-&`TIME `& set the maximum waiting time for a query
-.endd
+.itable none 0 0 2 20* left 80* left
+.irow DEREFERENCE "set the dereferencing parameter"
+.irow NETTIME "set a timeout for a network operation"
+.irow USER "set the DN, for authenticating the LDAP bind"
+.irow PASS "set the password, likewise"
+.irow REFERRALS "set the referrals parameter"
+.irow SERVERS "set alternate server list for this query only"
+.irow SIZE "set the limit for the number of entries returned"
+.irow TIME "set the maximum waiting time for a query"
+.endtable
The value of the DEREFERENCE parameter must be one of the words &"never"&,
&"searching"&, &"finding"&, or &"always"&. The value of the REFERRALS parameter
must be &"follow"& (the default) or &"nofollow"&. The latter stops the LDAP
-.section "Format of data returned by LDAP" "SECID71"
+.subsection "Format of data returned by LDAP" SECID71
.cindex "LDAP" "returned data formats"
The &(ldapdn)& lookup type returns the Distinguished Name from a single entry
as a sequence of values, for example
with a newline between the data for each row.
-.section "More about MySQL, PostgreSQL, Oracle, InterBase, and Redis" "SECID72"
+.subsection "More about MySQL, PostgreSQL, Oracle, InterBase, and Redis" SECID72
.cindex "MySQL" "lookup type"
.cindex "PostgreSQL lookup type"
.cindex "lookup" "MySQL"
The &%quote_redis%& expansion operator
escapes whitespace and backslash characters with a backslash.
-.section "Specifying the server in the query" "SECTspeserque"
+.subsection "Specifying the server in the query" SECTspeserque
For MySQL, PostgreSQL and Redis lookups (but not currently for Oracle and InterBase),
it is possible to specify a list of servers with an individual query. This is
done by appending a comma-separated option to the query type:
&*Note*&: server specifications in list-style lookups are still problematic.
-.section "Special MySQL features" "SECID73"
+.subsection "Special MySQL features" SECID73
For MySQL, an empty host name or the use of &"localhost"& in &%mysql_servers%&
causes a connection to the server on the local host by means of a Unix domain
socket. An alternate socket can be specified in parentheses.
is zero because no rows are affected.
-.section "Special PostgreSQL features" "SECID74"
+.subsection "Special PostgreSQL features" SECID74
PostgreSQL lookups can also use Unix domain socket connections to the database.
This is usually faster and costs less CPU time than a TCP/IP connection.
However it can be used only if the mail server runs on the same machine as the
update, or delete command), the result of the lookup is the number of rows
affected.
-.section "More about SQLite" "SECTsqlite"
+.subsection "More about SQLite" SECTsqlite
.cindex "lookup" "SQLite"
.cindex "sqlite lookup type"
SQLite is different to the other SQL lookups because a filename is required in
to 5 seconds, but it can be changed by means of the &%sqlite_lock_timeout%&
option.
-.section "More about Redis" "SECTredis"
+.subsection "More about Redis" SECTredis
.cindex "lookup" "Redis"
.cindex "redis lookup type"
Redis is a non-SQL database. Commands are simple get and set.
+.section "Results of list checking" SECTlistresults
+The primary result of doing a list check is a truth value.
+In some contexts additional information is stored
+about the list element that matched:
+.vlist
+.vitem hosts
+A &%hosts%& ACL condition
+will store a result in the &$host_data$& variable.
+.vitem local_parts
+A &%local_parts%& router option or &%local_parts%& ACL condition
+will store a result in the &$local_part_data$& variable.
+.vitem domains
+A &%domains%& router option or &%domains%& ACL condition
+will store a result in the &$domain_data$& variable.
+.vitem senders
+A &%senders%& router option or &%senders%& ACL condition
+will store a result in the &$sender_data$& variable.
+.vitem recipients
+A &%recipients%& ACL condition
+will store a result in the &$recipient_data$& variable.
+.endlist
+
+The detail of the additional information depends on the
+type of match and is given below as the &*value*& information.
+
+
+
+
.section "Expansion of lists" "SECTlistexpand"
.cindex "expansion" "of lists"
Each list is expanded as a single string before it is used.
-.section "Negated items in lists" "SECID76"
+.subsection "Negated items in lists" SECID76
.cindex "list" "negation"
.cindex "negation" "in lists"
Items in a list may be positive or negative. Negative items are indicated by a
-.section "File names in lists" "SECTfilnamlis"
+.subsection "File names in lists" SECTfilnamlis
.cindex "list" "filename in"
If an item in a domain, host, address, or local part list is an absolute
filename (beginning with a slash character), each line of the file is read and
-.section "An lsearch file is not an out-of-line list" "SECID77"
+.subsection "An lsearch file is not an out-of-line list" SECID77
As will be described in the sections that follow, lookups can be used in lists
to provide indexed methods of checking list membership. There has been some
confusion about the way &(lsearch)& lookups work in lists. Because
-.section "Results of list checking" SECTlistresults
-The primary result of doing a list check is a truth value.
-In some contexts additional information is stored
-about the list element that matched:
-.vlist
-.vitem hosts
-A &%hosts%& ACL condition
-will store a result in the &$host_data$& variable.
-.vitem local_parts
-A &%local_parts%& router option or &%local_parts%& ACL condition
-will store a result in the &$local_part_data$& variable.
-.vitem domains
-A &%domains%& router option or &%domains%& ACL condition
-will store a result in the &$domain_data$& variable.
-.vitem senders
-A &%senders%& router option or &%senders%& ACL condition
-will store a result in the &$sender_data$& variable.
-.vitem recipients
-A &%recipients%& ACL condition
-will store a result in the &$recipient_data$& variable.
-.endlist
-
-The detail of the additional information depends on the
-type of match and is given below as the &*value*& information.
-
-
-
-
-.section "Named lists" "SECTnamedlists"
+.subsection "Named lists" SECTnamedlists
.cindex "named lists"
.cindex "list" "named"
A list of domains, hosts, email addresses, or local parts can be given a name
-.section "Named lists compared with macros" "SECID78"
+.subsection "Named lists compared with macros" SECID78
.cindex "list" "named compared with macro"
.cindex "macro" "compared with named list"
At first sight, named lists might seem to be no different from macros in the
.endd
-.section "Named list caching" "SECID79"
+.subsection "Named list caching" SECID79
.cindex "list" "caching of named"
.cindex "caching" "named lists"
While processing a message, Exim caches the result of checking a named list if
&$domain_data$& variable and can be referred to in other router options or
other statements in the same ACL.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using ACL domains condition"
The value will be untainted.
&*Note*&: If the data result of the lookup (as opposed to the key)
&%domains%& option on a router, the value is preserved in the &$domain_data$&
variable and can be referred to in other options.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using router domains option"
The value will be untainted.
.next
involved, to ensure that the right value is being used as the key.
-.section "Special host list patterns" "SECID80"
+.subsection "Special host list patterns" SECID80
.cindex "empty item in hosts list"
.cindex "host list" "empty string in"
If a host list item is the empty string, it matches only when no remote host is
-.section "Host list patterns that match by IP address" "SECThoslispatip"
+.subsection "Host list patterns that match by IP address" SECThoslispatip
.cindex "host list" "matching IP addresses"
If an IPv4 host calls an IPv6 host and the call is accepted on an IPv6 socket,
the incoming address actually appears in the IPv6 host as
-.section "Host list patterns for single-key lookups by host address" &&&
- "SECThoslispatsikey"
+.subsection "Host list patterns for single-key lookups by host address" &&&
+ SECThoslispatsikey
.cindex "host list" "lookup of IP address"
When a host is to be identified by a single-key lookup of its complete IP
address, the pattern takes this form:
-.section "Host list patterns that match by host name" "SECThoslispatnam"
+.subsection "Host list patterns that match by host name" SECThoslispatnam
.cindex "host" "lookup failures"
.cindex "unknown host name"
.cindex "host list" "matching host name"
-.section "Behaviour when an IP address or name cannot be found" "SECTbehipnot"
+.subsection "Behaviour when an IP address or name cannot be found" SECTbehipnot
.cindex "host" "lookup failures, permanent"
While processing a host list, Exim may need to look up an IP address from a
name (see section &<<SECThoslispatip>>&), or it may need to look up a host name
list. The effect of each one lasts until the next, or until the end of the
list.
-.section "Mixing wildcarded host names and addresses in host lists" &&&
- "SECTmixwilhos"
+.subsection "Mixing wildcarded host names and addresses in host lists" &&&
+ SECTmixwilhos
.cindex "host list" "mixing names and addresses in"
This section explains the host/ip processing logic with the same concepts
.endlist
-.section "Temporary DNS errors when looking up host information" &&&
- "SECTtemdnserr"
+.subsection "Temporary DNS errors when looking up host information" &&&
+ SECTtemdnserr
.cindex "host" "lookup failures, temporary"
.cindex "&`+include_defer`&"
.cindex "&`+ignore_defer`&"
-.section "Host list patterns for single-key lookups by host name" &&&
- "SECThoslispatnamsk"
+.subsection "Host list patterns for single-key lookups by host name" &&&
+ SECThoslispatnamsk
.cindex "unknown host name"
.cindex "host list" "matching host name"
If a pattern is of the form
-.section "Host list patterns for query-style lookups" "SECID81"
+.subsection "Host list patterns for query-style lookups" SECID81
If a pattern is of the form
.display
<&'query-style-search-type'&>;<&'query'&>
-.section "Case of letters in address lists" "SECTcasletadd"
+.subsection "Case of letters in address lists" SECTcasletadd
.cindex "case of local parts"
.cindex "address list" "case forcing"
.cindex "case forcing in address lists"
database lookups, and the use of expansion operators such as &%sg%&, &%substr%&
and &%nhash%&.
+.new
+When reading lines from the standard input,
+macros can be defined and ACL variables can be set.
+For example:
+.code
+MY_MACRO = foo
+set acl_m_myvar = bar
+.endd
+Such macros and variables can then be used in later input lines.
+.wen
+
Exim gives up its root privilege when it is called with the &%-be%& option, and
instead runs under the uid and gid it was called with, to prevent users from
using &%-be%& for reading files to which they do not have access.
default, but the separator can be changed in the usual way (&<<SECTlistsepchange>>&).
For each item
in this list, its value is place in &$item$&, and then the condition is
-evaluated. If the condition is true, &$item$& is added to the output as an
+evaluated.
+.new
+Any modification of &$value$& by this evaluation is discarded.
+.wen
+If the condition is true, &$item$& is added to the output as an
item in a new list; if the condition is false, the item is discarded. The
separator used for the output list is the same as the one used for the
input, but a separator setting is not included in the output. For example:
${filter{a:b:c}{!eq{$item}{b}}}
.endd
yields &`a:c`&. At the end of the expansion, the value of &$item$& is restored
-to what it was before. See also the &%map%& and &%reduce%& expansion items.
+to what it was before.
+See also the &%map%& and &%reduce%& expansion items.
.vitem &*${hash{*&<&'string1'&>&*}{*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&
restored to what they were before. See also the &%filter%& and &%map%&
expansion items.
+. A bit of a special-case logic error in writing an expansion;
+. probably not worth including in the mainline of documentation.
+. If only we had footnotes (the html output variant is the problem).
+.
+. .new
+. &*Note*&: if an &'expansion condition'& is used in <&'string3'&>
+. and that condition modifies &$value$&,
+. then the string expansions dependent on the condition cannot use
+. the &$value$& of the reduce iteration.
+. .wen
+
.vitem &*$rheader_*&<&'header&~name'&>&*:*&&~or&~&*$rh_*&<&'header&~name'&>&*:*&
This item inserts &"raw"& header lines. It is described with the &%header%&
expansion item in section &<<SECTexpansionitems>>& above.
.cindex "expansion" "running a command"
.cindex "&%run%& expansion item"
This item runs an external command, as a subprocess.
-.new
One option is supported after the word &'run'&, comma-separated.
If the option &'preexpand'& is not used,
a shell, you must explicitly code it.
The command name may not be tainted, but the remaining arguments can be.
+&*Note*&: if tainted arguments are used, they are supplied by a
+potential attacker;
+a careful assessment for security vulnerabilities should be done.
+
If the option &'preexpand'& is used,
-.wen
the command and its arguments are first expanded as one string. The result is
split apart into individual arguments by spaces, and then the command is run
as above.
around the command arguments. A possible guard against this is to wrap the
variable in the &%sg%& operator to change any quote marks to some other
character.
-.new
Neither the command nor any argument may be tainted.
-.wen
The standard input for the command exists, but is empty. The standard output
and standard error are set to the same file descriptor.
-.vitem &*${substr{*&<&'string1'&>&*}{*&<&'string2'&>&*}{*&<&'string3'&>&*}}*&
+.vitem &*${substr{*&<&'start'&>&*}{*&<&'len'&>&*}{*&<&'subject'&>&*}}*&
.cindex "&%substr%& expansion item"
.cindex "substring extraction"
.cindex "expansion" "substring extraction"
The three strings are expanded; the first two must yield numbers. Call them
<&'n'&> and <&'m'&>. If you are using fixed values for these numbers, that is,
-if <&'string1'&> and <&'string2'&> do not change when they are expanded, you
+if <&'start'&> and <&'len'&> do not change when they are expanded, you
can use the simpler operator notation that avoids some of the braces:
.code
-${substr_<n>_<m>:<string>}
+${substr_<n>_<m>:<subject>}
.endd
The second number is optional (in both notations).
If it is absent in the simpler format, the preceding underscore must also be
Since this operation is expected to
be mostly used for looking up masked addresses in files, the
-.new
normal
-.wen
result for an IPv6
address uses dots to separate components instead of colons, because colon
terminates a key string in lsearch files. So, for example,
.code
3ffe.ffff.836f.0a00.000a.0800.2000.0000/99
.endd
-.new
If the optional form &*mask_n*& is used, IPv6 address result are instead
returned in normailsed form, using colons and with zero-compression.
-.wen
Letters in IPv6 addresses are always output in lower case.
.cindex "expansion" "numeric comparison"
There are a number of symbolic operators for doing numeric comparisons. They
are:
-.display
-&`= `& equal
-&`== `& equal
-&`> `& greater
-&`>= `& greater or equal
-&`< `& less
-&`<= `& less or equal
-.endd
+.itable none 0 0 2 10* left 90* left
+.irow "= " "equal"
+.irow "== " "equal"
+.irow "> " "greater"
+.irow ">= " "greater or equal"
+.irow "< " "less"
+.irow "<= " "less or equal"
+.endtable
For example:
.code
${if >{$message_size}{10M} ...
.cindex "first delivery"
.cindex "expansion" "first delivery test"
.cindex "&%first_delivery%& expansion condition"
+.cindex retry condition
This condition, which has no data, is true during a message's first delivery
attempt. It is false during any subsequent delivery attempts.
${if forany{fOo:NeeDLE:bAr}{eqi{$item}{Needle}}}
.endd
-.new
The variable &$value$& will be set for a successful match and can be
used in the success clause of an &%if%& expansion item using the condition.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using an inlist expansion condition"
It will have the same taint status as the list; expansions such as
.code
${if inlist {$h_mycode:} {0 : 1 : 42} {$value}}
.endd
can be used for de-tainting.
Any previous &$value$& is restored after the if.
-.wen
.vitem &*isip&~{*&<&'string'&>&*}*& &&&
have their local parts matched casefully. Domains are always matched
caselessly.
-.new
The variable &$value$& will be set for a successful match and can be
used in the success clause of an &%if%& expansion item using the condition.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using a match_local_part expansion condition"
It will have the same taint status as the list; expansions such as
.code
${if match_local_part {$local_part} {alice : bill : charlotte : dave} {$value}}
.endd
can be used for de-tainting.
Any previous &$value$& is restored after the if.
-.wen
Note that <&'string2'&> is not itself subject to string expansion, unless
Exim was built with the EXPAND_LISTMATCH_RHS option.
This section contains an alphabetical list of all the expansion variables. Some
of them are available only when Exim is compiled with specific options such as
support for TLS or the content scanning extension.
+.cindex "tainted data"
+Variables marked as &'tainted'& are likely to carry data supplied by
+a potential attacker.
+Variables without such marking may also, depending on how their
+values are created.
+Such variables should not be further expanded,
+used as filenames
+or used as command-line arguments for external commands.
.vlist
.vitem "&$0$&, &$1$&, etc"
precedes the expansion of the string. For example, the commands available in
Exim filter files include an &%if%& command with its own regular expression
matching condition.
+If the subject string was tainted then any captured substring will also be.
.vitem "&$acl_arg1$&, &$acl_arg2$&, etc"
Within an acl condition, expansion condition or expansion item
the ACL's as well.
-.vitem &$authenticated_sender$&
+.tvar &$authenticated_sender$&
.cindex "sender" "authenticated"
.cindex "authentication" "sender"
.cindex "AUTH" "on MAIL command"
-.vindex "&$authenticated_sender$&"
When acting as a server, Exim takes note of the AUTH= parameter on an incoming
SMTP MAIL command if it believes the sender is sufficiently trusted, as
described in section &<<SECTauthparamail>>&. Unless the data is the string
possible to distinguish between &"did not try to authenticate"&
(&$sender_host_authenticated$& is empty and &$authentication_failed$& is set to
&"0"&) and &"tried to authenticate but failed"& (&$sender_host_authenticated$&
-is empty and &$authentication_failed$& is set to &"1"&). Failure includes any
-negative response to an AUTH command, including (for example) an attempt to use
-an undefined mechanism.
+is empty and &$authentication_failed$& is set to &"1"&).
+Failure includes cancellation of a authentication attempt,
+and any negative response to an AUTH command,
+(including, for example, an attempt to use an undefined mechanism).
.vitem &$av_failed$&
.cindex "content scanning" "AV scanner failure"
looked up, the contents of any associated TXT record, and the value from the
main A record. See section &<<SECID204>>& for more details.
-.vitem &$domain$&
-.vindex "&$domain$&"
+.tvar &$domain$&
When an address is being routed, or delivered on its own, this variable
contains the domain. Uppercase letters in the domain are converted into lower
case for &$domain$&.
This value may be overridden by the &%exim_version%& main config option.
.vitem &$header_$&<&'name'&>
+.tmark
This is not strictly an expansion variable. It is expansion syntax for
inserting the message header line with the given name. Note that the name must
be terminated by colon or white space, because it may contain a wide variety of
deny hosts = net-lsearch;/some/file
message = $host_data
.endd
+
.vitem &$host_lookup_deferred$&
.cindex "host name" "lookup, failure of"
.vindex "&$host_lookup_deferred$&"
is an integer. For example, if the load average is 0.21, the value of the
variable is 210. The value is recomputed every time the variable is referenced.
-.vitem &$local_part$&
-.vindex "&$local_part$&"
+.tvar &$local_part$&
When an address is being routed, or delivered on its own, this
variable contains the local part. When a number of addresses are being
delivered together (for example, multiple RCPT commands in an SMTP
of seconds since the message was received. It does not change during a single
delivery attempt.
-.vitem &$message_body$&
+.tvar &$message_body$&
.cindex "body of message" "expansion variable"
.cindex "message body" "in expansion"
.cindex "binary zero" "in message body"
-.vindex "&$message_body$&"
.oindex "&%message_body_visible%&"
This variable contains the initial portion of a message's body while it is
being delivered, and is intended mainly for use in filter files. The maximum
this can be disabled by setting &%message_body_newlines%& to be true. Binary
zeros are always converted into spaces.
-.vitem &$message_body_end$&
+.tvar &$message_body_end$&
.cindex "body of message" "expansion variable"
.cindex "message body" "in expansion"
-.vindex "&$message_body_end$&"
This variable contains the final portion of a message's
body while it is being delivered. The format and maximum size are as for
&$message_body$&.
line; it is the local id that Exim assigns to the message, for example:
&`1BXTIK-0001yO-VA`&.
-.vitem &$message_headers$&
-.vindex &$message_headers$&
+.tvar &$message_headers$&
This variable contains a concatenation of all the header lines when a message
is being processed, except for lines added by routers or transports. The header
lines are separated by newline characters. Their contents are decoded in the
same way as a header line that is inserted by &%bheader%&.
-.vitem &$message_headers_raw$&
-.vindex &$message_headers_raw$&
+.tvar &$message_headers_raw$&
This variable is like &$message_headers$& except that no processing of the
contents of header lines is done.
These variables are counters that can be incremented by means
of the &%add%& command in filter files.
-.vitem &$original_domain$&
+.tvar &$original_domain$&
.vindex "&$domain$&"
-.vindex "&$original_domain$&"
When a top-level address is being processed for delivery, this contains the
same value as &$domain$&. However, if a &"child"& address (for example,
generated by an alias, forward, or filter file) is being processed, this
filter, it is set up with an artificial &"parent"& address. This has the local
part &'system-filter'& and the default qualify domain.
-.vitem &$original_local_part$&
+.tvar &$original_local_part$&
.vindex "&$local_part$&"
-.vindex "&$original_local_part$&"
When a top-level address is being processed for delivery, this contains the
same value as &$local_part$&, unless a prefix or suffix was removed from the
local part, because &$original_local_part$& always contains the full local
For messages received by SMTP over TCP/IP, this is normally the uid of the Exim
user.
-.vitem &$parent_domain$&
-.vindex "&$parent_domain$&"
+.tvar &$parent_domain$&
This variable is similar to &$original_domain$& (see
above), except that it refers to the immediately preceding parent address.
-.vitem &$parent_local_part$&
-.vindex "&$parent_local_part$&"
+.tvar &$parent_local_part$&
This variable is similar to &$original_local_part$&
(see above), except that it refers to the immediately preceding parent address.
(described under &%transport_filter%& in chapter &<<CHAPtransportgeneric>>&).
It cannot be used in general expansion strings, and provokes an &"unknown
variable"& error if encountered.
+&*Note*&: This value permits data supplied by a potential attacker to
+be used in the command for a &(pipe)& transport.
+Such configurations should be carefully assessed for security vulnerbilities.
.vitem &$primary_hostname$&
.vindex "&$primary_hostname$&"
is available in the DATA ACL, the non-SMTP ACL, and while routing and
delivering.
-.vitem &$received_for$&
-.vindex "&$received_for$&"
+.tvar &$received_for$&
If there is only a single recipient address in an incoming message, this
variable contains that address when the &'Received:'& header line is being
built. The value is copied after recipient rewriting has happened, but before
The main use of this variable is expected to be to distinguish between
rejections of MAIL and rejections of RCPT.
-.vitem &$recipients$&
-.vindex "&$recipients$&"
+.tvar &$recipients$&
This variable contains a list of envelope recipients for a message. A comma and
a space separate the addresses in the replacement text. However, the variable
is not generally available, to prevent exposure of Bcc recipients in
When a &%regex%& or &%mime_regex%& ACL condition succeeds,
these variables contain the
captured substrings identified by the regular expression.
+If the subject string was tainted then so will any captured substring.
-.vitem &$reply_address$&
-.vindex "&$reply_address$&"
+.tvar &$reply_address$&
When a message is being processed, this variable contains the contents of the
&'Reply-To:'& header line if one exists and it is not empty, or otherwise the
contents of the &'From:'& header line. Apart from the removal of leading
happens, &$self_hostname$& is set to the name of the local host that the
original router encountered. In other circumstances its contents are null.
-.vitem &$sender_address$&
-.vindex "&$sender_address$&"
+.tvar &$sender_address$&
When a message is being processed, this variable contains the sender's address
that was received in the message's envelope. The case of letters in the address
is retained, in both the local part and the domain. For bounce messages, the
after the end of the current ACL statement. If you want to preserve it for
longer, you can save it in an ACL variable.
-.vitem &$sender_address_domain$&
-.vindex "&$sender_address_domain$&"
+.tvar &$sender_address_domain$&
The domain portion of &$sender_address$&.
-.vitem &$sender_address_local_part$&
-.vindex "&$sender_address_local_part$&"
+.tvar &$sender_address_local_part$&
The local part portion of &$sender_address$&.
.vitem &$sender_data$&
.cindex "DNS" "DNSSEC"
done using DNS information the resolver library stated was authenticated data.
-.vitem &$sender_helo_name$&
-.vindex "&$sender_helo_name$&"
+.tvar &$sender_helo_name$&
When a message is received from a remote host that has issued a HELO or EHLO
command, the argument of that command is placed in this variable. It is also
set if HELO or EHLO is used when a message is received using SMTP locally via
is known to currently ignore EDNS0, documented in CAVEATS of asr_run(3).
-.vitem &$sender_host_name$&
-.vindex "&$sender_host_name$&"
+.tvar &$sender_host_name$&
When a message is received from a remote host, this variable contains the
host's name as obtained by looking up its IP address. For messages received by
other means, this variable is empty.
&$smtp_active_hostname$& is saved with any message that is received, so its
value can be consulted during routing and delivery.
-.vitem &$smtp_command$&
-.vindex "&$smtp_command$&"
+.tvar &$smtp_command$&
During the processing of an incoming SMTP command, this variable contains the
entire command. This makes it possible to distinguish between HELO and EHLO in
the HELO ACL, and also to distinguish between commands such as these:
rewriting, whereas the values in &$local_part$& and &$domain$& are taken from
the address after SMTP-time rewriting.
-.vitem &$smtp_command_argument$&
+.tvar &$smtp_command_argument$&
.cindex "SMTP" "command, argument for"
-.vindex "&$smtp_command_argument$&"
While an ACL is running to check an SMTP command, this variable contains the
argument, that is, the text that follows the command name, with leading white
space removed. Following the introduction of &$smtp_command$&, this variable is
Observability for TLS session resumption. See &<<SECTresumption>>& for details.
-.vitem &$tls_in_sni$&
-.vindex "&$tls_in_sni$&"
+.tvar &$tls_in_sni$&
.vindex "&$tls_sni$&"
.cindex "TLS" "Server Name Indication"
.cindex "TLS" SNI
.row &%log_timezone%& "add timezone to log lines"
.row &%message_logs%& "create per-message logs"
.row &%preserve_message_logs%& "after message completion"
+.row &%panic_coredump%& "request coredump on fatal errors"
.row &%process_log_path%& "for SIGUSR1 and &'exiwhat'&"
.row &%slow_lookup_log%& "control logging of slow DNS lookups"
.row &%syslog_duplication%& "controls duplicate log lines on syslog"
.row &%gnutls_compat_mode%& "use GnuTLS compatibility mode"
.row &%gnutls_allow_auto_pkcs11%& "allow GnuTLS to autoload PKCS11 modules"
.row &%hosts_require_alpn%& "mandatory ALPN"
+.row &%hosts_require_helo%& "mandatory HELO/EHLO"
.row &%openssl_options%& "adjust OpenSSL compatibility options"
.row &%tls_advertise_hosts%& "advertise TLS to these hosts"
.row &%tls_alpn%& "acceptable protocol names"
.cindex "host" "rejecting connections from"
If this option is set, incoming SMTP calls from the hosts listed are rejected
as soon as the connection is made.
-This option is obsolete, and retained only for backward compatibility, because
+This option is mostly obsolete, retained for backward compatibility because
nowadays the ACL specified by &%acl_smtp_connect%& can also reject incoming
-connections immediately.
+connections immediately
+.new
+(except for tls-on-connect connections).
+.wen
The ability to give an immediate rejection (either by this option or using an
ACL) is provided for use in unusual cases. Many hosts will just try again,
.code
hosts_connection_nolog = :
.endd
-If the &%smtp_connection%& log selector is not set, this option has no effect.
+.new
+The hosts affected by this option also do not log "no MAIL in SMTP connection"
+lines, as may commonly be produced by a monitoring system.
+.wen
.option hosts_require_alpn main "host list&!!" unset
managed by this option, and should be done separately.
+.option hosts_require_helo main "host list&!!" *
+.cindex "HELO/EHLO" requiring
+Exim will require an accepted HELO or EHLO command from a host matching
+this list, before accepting a MAIL command.
+
+
.option hosts_proxy main "host list&!!" unset
.cindex proxy "proxy protocol"
This option enables use of Proxy Protocol proxies for incoming
The option is available only if Exim has been built with Oracle support.
+.new
+.option panic_coredump main boolean false
+This option is rarely needed but can help for some debugging investigations.
+If set, when an internal error is detected by Exim which is sufficient
+to terminate the process
+(all such are logged in the paniclog)
+then a coredump is requested.
+
+Note that most systems require additional administrative configuration
+to permit write a core file for a setuid program, which is Exim's
+common installed configuration.
+.wen
+
.option percent_hack_domains main "domain list&!!" unset
.cindex "&""percent hack""&"
.cindex "source routing" "in email address"
.option pipelining_connect_advertise_hosts main "host list&!!" *
.cindex "pipelining" "early connection"
-.cindex "pipelining" PIPE_CONNECT
-.cindex "ESMTP extensions" PIPE_CONNECT
-If Exim is built with the SUPPORT_PIPE_CONNECT build option
+.cindex "pipelining" PIPECONNECT
+.cindex "ESMTP extensions" PIPECONNECT
+If Exim is built without the DISABLE_PIPE_CONNECT build option
this option controls which hosts the facility is advertised to
and from which pipeline early-connection (before MAIL) SMTP
commands are acceptable.
See also the &%hosts_pipe_connect%& smtp transport option.
-The SMTP service extension keyword advertised is &"PIPE_CONNECT"&.
+The SMTP service extension keyword advertised is &"PIPECONNECT"&;
+it permits the client to pipeline
+TCP connection and hello command (inclear phase),
+or TLS-establishment and hello command (encrypted phase),
+on later connections to the same host.
.option prdr_enable main boolean false
next queue run. See also &%hold_domains%& and &%queue_smtp_domains%&.
-.option queue_fast_ramp main boolean false
+.option queue_fast_ramp main boolean true
.cindex "queue runner" "two phase"
.cindex "queue" "double scanning"
If set to true, two-phase queue runs, initiated using &%-qq%& on the
for the remaining recipients at a later time.
-.option remote_max_parallel main integer 2
+.option remote_max_parallel main integer 4
.cindex "delivery" "parallelism for remote"
This option controls parallel delivery of one message to a number of remote
hosts. If the value is less than 2, parallel delivery is disabled, and Exim
At this point, all of the "ike" values should be considered obsolete;
they are still in Exim to avoid breaking unusual configurations, but are
candidates for removal the next time we have backwards-incompatible changes.
-.new
Two of them in particular (&`ike1`& and &`ike22`&) are called out by RFC 8247
as MUST NOT use for IPSEC, and two more (&`ike23`& and &`ike24`&) as
SHOULD NOT.
are used, warnings will be logged in the paniclog, and if any are used then
warnings will be logged in the mainlog.
All four will be removed in a future Exim release.
-.wen
The TLS protocol does not negotiate an acceptable size for this; clients tend
to hard-drop connections if what is offered by the server is unacceptable,
holding password data (such as NIS) are supported. If the local part is a local
user,
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using router check_local_user option"
&$local_part_data$& is set to an untainted version of the local part and
&$home$& is set from the password data. The latter can be tested in other
preconditions that are evaluated after this one (the order of evaluation is
The expansion variables &$host$& and &$host_address$& are available when the
transport is a remote one. They contain the name and IP address of the host to
which the message is being sent. For example:
+. used to have $sender_address in this cmdline, but it's tainted
.code
transport_filter = /some/directory/transport-filter.pl \
- $host $host_address $sender_address $pipe_addresses
+ $host $host_address $pipe_addresses
.endd
Two problems arise if you want to use more complicated expansion items to
checking is done in "belowhome" mode.
.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using appendfile create_file option"
If "belowhome" checking is used, the file or directory path
becomes de-tainted.
the &%environment%& option can be used to add additional variables to this
environment. The environment for the &(pipe)& transport is not subject
to the &%add_environment%& and &%keep_environment%& main config options.
+&*Note*&: Using enviroment variables loses track of tainted data.
+Writers of &(pipe)& transport commands should be wary of data supplied
+by potential attackers.
.display
&`DOMAIN `& the domain of the address
&`HOME `& the home directory, if set
Exim, and each argument is separately expanded, as described in section
&<<SECThowcommandrun>>& above.
+.cindex "tainted data"
+No part of the resulting command may be tainted.
+
.option environment pipe string&!! unset
.cindex "&(pipe)& transport" "environment for command"
.cindex "Cyrus"
The next example shows a transport and a router for a system where local
deliveries are handled by the Cyrus IMAP server.
+. Used to have R: local_part_suffix = .* + T: -m $local_part_suffix_v
+. but that suffix is tainted so cannot be used in a command arg
+. Really, you'd want to use a lookup for acceptable suffixes to do real detainting
.code
# transport
local_delivery_cyrus:
driver = pipe
command = /usr/cyrus/bin/deliver \
- -m ${substr_1:$local_part_suffix} -- $local_part
+ -- $local_part_data
user = cyrus
group = mail
return_output
local_user_cyrus:
driver = accept
check_local_user
- local_part_suffix = .*
transport = local_delivery_cyrus
.endd
Note the unsetting of &%message_prefix%& and &%message_suffix%&, and the use of
The use of &%helo_data%& applies both to sending messages and when doing
callouts.
+.option host_name_extract smtp "string list&!!" "see below"
+.cindex "load balancer" "hosts behind"
+.cindex TLS resumption
+Some mail-accepting sites
+(notably Microsoft)
+operate many servers behind a network load-balancer. When this is done,
+with separated TLS session caches, TLS session resuption becomes problematic.
+It will only succeed when the same server happens to be selected by the
+load-balancer, matching the session stored in the client's cache.
+
+Exim can pull out a server name, if there is one, from the response to the
+client's SMTP EHLO command.
+The default value of this option:
+.code
+ ${if and { {match {$host} {.outlook.com\$}} \
+ {match {$item} {\N^250-([\w.]+)\s\N}} \
+ } {$1}}
+.endd
+suffices for one known case.
+During the expansion of this option the &$item$& variable will have the
+server's EHLO response.
+The result of the option expansion is included in the key used to store and
+retrieve the TLS session, for session resumption.
+
+Operators of high-load sites may wish to evaluate their logs for indications
+of other destination sites operating load-balancers, and develop a suitable
+expression for this option.
+The smtp:ehlo event and the &$tls_out_resumption$& variable
+will be useful for such work.
+
.option hosts smtp "string list&!!" unset
Hosts are associated with an address by a router such as &(dnslookup)&, which
finds the hosts by looking up the address domain in the DNS, or by
.option hosts_pipe_connect smtp "host list&!!" unset
.cindex "pipelining" "early connection"
-.cindex "pipelining" PIPE_CONNECT
+.cindex "pipelining" PIPECONNECT
If Exim is built with the SUPPORT_PIPE_CONNECT build option
this option controls which to hosts the facility watched for
and recorded, and used for subsequent connections.
See also the &%pipelining_connect_advertise_hosts%& main option.
Note:
-.new
When the facility is used, if the transport &%interface%& option is unset
the &%helo_data%& option
-.wen
will be expanded before the &$sending_ip_address$& variable
is filled in.
A check is made for the use of that variable, without the
&<<CHAPSMTPAUTH>>& for details of authentication.
-.option hosts_request_ocsp smtp "host list&!!" *
+.option hosts_request_ocsp smtp "host list&!!" "see below"
.cindex "TLS" "requiring for certain servers"
Exim will request a Certificate Status on a
TLS session for any host that matches this list.
&%tls_verify_certificates%& should also be set for the transport.
+.new
+The default is &"**"& if DANE is not in use for the connection,
+or if DANE-TA us used.
+It is empty if DANE-EE is used.
+.wen
+
.option hosts_require_alpn smtp "host list&!!" unset
.cindex ALPN "require negotiation in client"
.cindex TLS ALPN
See the &%dnssec_request_domains%& router and transport options.
See section &<<SECDANE>>&.
-.option hosts_require_helo smtp "host list&!!" *
-.cindex "HELO/EHLO" requiring
-Exim will require an accepted HELO or EHLO command from a host matching
-this list, before accepting a MAIL command.
-
.option hosts_require_ocsp smtp "host list&!!" unset
.cindex "TLS" "requiring for certain servers"
Exim will request, and check for a valid Certificate Status being given, on a
operation is as if this option selected all hosts.
&*Warning*&: Including a host in &%tls_verify_hosts%& does not require
that connections use TLS.
-Fallback to in-clear communication will be done unless restricted by
+Fallback to in-clear communication will be done unless restricted by
the &%hosts_require_tls%& option.
.option utf8_downconvert smtp integer&!! -1
.vindex "&$sender_address$&"
At the start of an ACL for MAIL, the sender address may have been rewritten
-by a special SMTP-time rewrite rule (see section &<<SECTrewriteS>>&), but no
+by a special SMTP-time rewrite rule (see section &<<SSECTrewriteS>>&), but no
ordinary rewrite rules have yet been applied. If, however, the sender address
is verified in the ACL, it is rewritten before verification, and remains
rewritten thereafter. The subsequent value of &$sender_address$& is the
-.section "Rewriting flags" "SECID153"
+.subsection "Rewriting flags" "SSECID153"
There are three different kinds of flag that may appear on rewriting rules:
.ilist
-.section "Flags specifying which headers and envelope addresses to rewrite" &&&
- "SECID154"
-.cindex "rewriting" "flags"
+.subsection "Flags specifying which headers and envelope addresses to rewrite" &&&
+ "SSECID154"
+.cindex rewriting flags
If none of the following flag letters, nor the &"S"& flag (see section
-&<<SECTrewriteS>>&) are present, a main rewriting rule applies to all headers
+&<<SSECTrewriteS>>&) are present, a main rewriting rule applies to all headers
and to both the sender and recipient fields of the envelope, whereas a
transport-time rewriting rule just applies to all headers. Otherwise, the
rewriting rule is skipped unless the relevant addresses are being processed.
restrict this to special known cases in your own domains.
-.section "The SMTP-time rewriting flag" "SECTrewriteS"
-.cindex "SMTP" "rewriting malformed addresses"
-.cindex "RCPT" "rewriting argument of"
-.cindex "MAIL" "rewriting argument of"
+.subsection "The SMTP-time rewriting flag" SSECTrewriteS
+.cindex SMTP "rewriting malformed addresses"
+.cindex RCPT "rewriting argument of"
+.cindex MAIL "rewriting argument of"
The rewrite flag &"S"& specifies a rewrite of incoming envelope addresses at
SMTP time, as soon as an address is received in a MAIL or RCPT command, and
before any other processing; even before syntax checking. The pattern is
original address in the MAIL or RCPT command.
-.section "Flags controlling the rewriting process" "SECID155"
+.subsection "Flags controlling the rewriting process" SSECID155
There are four flags which control the way the rewriting process works. These
take effect only when a rule is invoked, that is, when the address is of the
correct type (matches the flags) and matches the pattern:
.cindex "ESMTP extensions" AUTH
Very briefly, the way SMTP authentication works is as follows:
-.ilist
+.olist
The server advertises a number of authentication &'mechanisms'& in response to
the client's EHLO command.
.next
Successful authentication sets up information used by the
&%authresults%& expansion item.
-
+.new
+.cindex authentication "failure event, server"
+If an authenticator is run and does not succeed,
+an event (see &<<CHAPevents>>&) of type "auth:fail" is raised.
+While the event is being processed the variables
+&$sender_host_authenticated$& (with the authenticator name)
+and &$authenticated_fail_id$& (as set by the authenticator &%server_set_id%& option)
+will be valid.
+If the event is serviced and a string is returned then the string will be logged
+instead of the default log line.
+See <<CHAPevents>> for details on events.
+.wen
.section "Testing server authentication" "SECID169"
Exim abandons trying to send the message to the host for the moment. It will
try again later. If there are any backup hosts available, they are tried in the
usual way.
+
+.new
+.next
+.cindex authentication "failure event, client"
+If the response to authentication is a permanent error (5&'xx'& code),
+an event (see &<<CHAPevents>>&) of type "auth:fail" is raised.
+While the event is being processed the variable
+&$sender_host_authenticated$& (with the authenticator name)
+will be valid.
+If the event is serviced and a string is returned then the string will be logged.
+See <<CHAPevents>> for details on events.
+.wen
+
.next
If the response to authentication is a permanent error (5&'xx'& code), Exim
carries on searching the list of authenticators and tries another one if
(again depending on the &%tls_cipher%& log selector).
-.section "Requesting and verifying client certificates" "SECID183"
+.subsection "Requesting and verifying client certificates"
.cindex "certificate" "verification of client"
.cindex "TLS" "client certificate verification"
If you want an Exim server to request a certificate when negotiating a TLS
certificate is supplied, &$tls_in_peerdn$& is empty.
-.section "Revoked certificates" "SECID184"
-.cindex "TLS" "revoked certificates"
-.cindex "revocation list"
-.cindex "certificate" "revocation list"
-.cindex "OCSP" "stapling"
-Certificate issuing authorities issue Certificate Revocation Lists (CRLs) when
-certificates are revoked. If you have such a list, you can pass it to an Exim
-server using the global option called &%tls_crl%& and to an Exim client using
-an identically named option for the &(smtp)& transport. In each case, the value
-of the option is expanded and must then be the name of a file that contains a
-CRL in PEM format.
-The downside is that clients have to periodically re-download a potentially huge
-file from every certificate authority they know of.
-
-The way with most moving parts at query time is Online Certificate
-Status Protocol (OCSP), where the client verifies the certificate
-against an OCSP server run by the CA. This lets the CA track all
-usage of the certs. It requires running software with access to the
-private key of the CA, to sign the responses to the OCSP queries. OCSP
-is based on HTTP and can be proxied accordingly.
-
-The only widespread OCSP server implementation (known to this writer)
-comes as part of OpenSSL and aborts on an invalid request, such as
-connecting to the port and then disconnecting. This requires
-re-entering the passphrase each time some random client does this.
-
-The third way is OCSP Stapling; in this, the server using a certificate
-issued by the CA periodically requests an OCSP proof of validity from
-the OCSP server, then serves it up inline as part of the TLS
-negotiation. This approach adds no extra round trips, does not let the
-CA track users, scales well with number of certs issued by the CA and is
-resilient to temporary OCSP server failures, as long as the server
-starts retrying to fetch an OCSP proof some time before its current
-proof expires. The downside is that it requires server support.
-
-Unless Exim is built with the support disabled,
-or with GnuTLS earlier than version 3.3.16 / 3.4.8
-support for OCSP stapling is included.
-
-There is a global option called &%tls_ocsp_file%&.
-The file specified therein is expected to be in DER format, and contain
-an OCSP proof. Exim will serve it as part of the TLS handshake. This
-option will be re-expanded for SNI, if the &%tls_certificate%& option
-contains &`tls_in_sni`&, as per other TLS options.
-
-Exim does not at this time implement any support for fetching a new OCSP
-proof. The burden is on the administrator to handle this, outside of
-Exim. The file specified should be replaced atomically, so that the
-contents are always valid. Exim will expand the &%tls_ocsp_file%& option
-on each connection, so a new file will be handled transparently on the
-next connection.
-
-When built with OpenSSL Exim will check for a valid next update timestamp
-in the OCSP proof; if not present, or if the proof has expired, it will be
-ignored.
-
-For the client to be able to verify the stapled OCSP the server must
-also supply, in its stapled information, any intermediate
-certificates for the chain leading to the OCSP proof from the signer
-of the server certificate. There may be zero or one such. These
-intermediate certificates should be added to the server OCSP stapling
-file named by &%tls_ocsp_file%&.
-
-Note that the proof only covers the terminal server certificate,
-not any of the chain from CA to it.
-
-There is no current way to staple a proof for a client certificate.
-
-.code
- A helper script "ocsp_fetch.pl" for fetching a proof from a CA
- OCSP server is supplied. The server URL may be included in the
- server certificate, if the CA is helpful.
-
- One failure mode seen was the OCSP Signer cert expiring before the end
- of validity of the OCSP proof. The checking done by Exim/OpenSSL
- noted this as invalid overall, but the re-fetch script did not.
-.endd
-
-
-.section "Caching of static server configuration items" "SECTserverTLScache"
+.subsection "Caching of static server configuration items" "SSECTserverTLScache"
.cindex certificate caching
.cindex privatekey caching
.cindex crl caching
-.section "Caching of static client configuration items" "SECTclientTLScache"
+.subsection "Caching of static client configuration items" SECTclientTLScache
.cindex certificate caching
.cindex privatekey caching
.cindex crl caching
only point of caution. The &$tls_out_sni$& variable will be set to this string
for the lifetime of the client connection (including during authentication).
-.new
If DANE validated the connection attempt then the value of the &%tls_sni%& option
is forced to the name of the destination host, after any MX- or CNAME-following.
-.wen
Except during SMTP client sessions, if &$tls_in_sni$& is set then it is a string
received from a client.
0.5.10. (Its presence predates the current API which Exim uses, so if Exim
built, then you have SNI support).
+.subsection ALPN
.cindex TLS ALPN
.cindex ALPN "general information"
.cindex TLS "Application Layer Protocol Names"
The client for the connection proposes a set of protocol names, and
the server responds with a selected one.
It is not, as of 2021, commonly used for SMTP connections.
-However, to guard against misirected or malicious use of web clients
+However, to guard against misdirected or malicious use of web clients
(which often do use ALPN) against MTA ports, Exim by default check that
there is no incompatible ALPN specified by a client for a TLS connection.
If there is, the connection is rejected.
&%tls_alpn%& and &%hosts_require_alpn%&.
There are no variables providing observability.
Some feature-specific logging may appear on denied connections, but this
-depends on the behavious of the peer
+depends on the behaviour of the peer
(not all peers can send a feature-specific TLS Alert).
This feature is available when Exim is built with
&url(https://www.ssllabs.com/).
-.section "Certificate chains" "SECID186"
+.subsection "Certificate chains" SECID186
A file named by &%tls_certificate%& may contain more than one
certificate. This is useful in the case where the certificate that is being
sent is validated by an intermediate certificate which the other end does
-.section "Self-signed certificates" "SECID187"
+.subsection "Self-signed certificates" SECID187
.cindex "certificate" "self-signed"
You can create a self-signed certificate using the &'req'& command provided
with OpenSSL, like this:
user certificates, see the &'General implementation overview'& chapter of the
Open-source PKI book, available online at
&url(https://sourceforge.net/projects/ospkibook/).
+
+
+.subsection "Revoked certificates"
+.cindex "TLS" "revoked certificates"
+.cindex "revocation list"
+.cindex "certificate" "revocation list"
+.cindex "OCSP" "stapling"
+There are three ways for a certificate to be made unusable
+before its expiry.
+
+.ilist
+Certificate issuing authorities issue Certificate Revocation Lists (CRLs) when
+certificates are revoked. If you have such a list, you can pass it to an Exim
+server using the global option called &%tls_crl%& and to an Exim client using
+an identically named option for the &(smtp)& transport. In each case, the value
+of the option is expanded and must then be the name of a file that contains a
+CRL in PEM format.
+The downside is that clients have to periodically re-download a potentially huge
+file from every certificate authority they know of.
+
+.next
+The way with most moving parts at query time is Online Certificate
+Status Protocol (OCSP), where the client verifies the certificate
+against an OCSP server run by the CA. This lets the CA track all
+usage of the certs. It requires running software with access to the
+private key of the CA, to sign the responses to the OCSP queries. OCSP
+is based on HTTP and can be proxied accordingly.
+
+The only widespread OCSP server implementation (known to this writer)
+comes as part of OpenSSL and aborts on an invalid request, such as
+connecting to the port and then disconnecting. This requires
+re-entering the passphrase each time some random client does this.
+
+.next
+The third way is OCSP Stapling; in this, the server using a certificate
+issued by the CA periodically requests an OCSP proof of validity from
+the OCSP server, then serves it up inline as part of the TLS
+negotiation. This approach adds no extra round trips, does not let the
+CA track users, scales well with number of certs issued by the CA and is
+resilient to temporary OCSP server failures, as long as the server
+starts retrying to fetch an OCSP proof some time before its current
+proof expires. The downside is that it requires server support.
+
+Unless Exim is built with the support disabled,
+or with GnuTLS earlier than version 3.3.16 / 3.4.8
+support for OCSP stapling is included.
+
+There is a global option called &%tls_ocsp_file%&.
+The file specified therein is expected to be in DER format, and contain
+an OCSP proof. Exim will serve it as part of the TLS handshake. This
+option will be re-expanded for SNI, if the &%tls_certificate%& option
+contains &`tls_in_sni`&, as per other TLS options.
+
+Exim does not at this time implement any support for fetching a new OCSP
+proof. The burden is on the administrator to handle this, outside of
+Exim. The file specified should be replaced atomically, so that the
+contents are always valid. Exim will expand the &%tls_ocsp_file%& option
+on each connection, so a new file will be handled transparently on the
+next connection.
+
+When built with OpenSSL Exim will check for a valid next update timestamp
+in the OCSP proof; if not present, or if the proof has expired, it will be
+ignored.
+
+For the client to be able to verify the stapled OCSP the server must
+also supply, in its stapled information, any intermediate
+certificates for the chain leading to the OCSP proof from the signer
+of the server certificate. There may be zero or one such. These
+intermediate certificates should be added to the server OCSP stapling
+file named by &%tls_ocsp_file%&.
+
+Note that the proof only covers the terminal server certificate,
+not any of the chain from CA to it.
+
+There is no current way to staple a proof for a client certificate.
+
+.code
+ A helper script "ocsp_fetch.pl" for fetching a proof from a CA
+ OCSP server is supplied. The server URL may be included in the
+ server certificate, if the CA is helpful.
+
+ One failure mode seen was the OCSP Signer cert expiring before the end
+ of validity of the OCSP proof. The checking done by Exim/OpenSSL
+ noted this as invalid overall, but the re-fetch script did not.
+.endd
+.endlist
+
+
.ecindex IIDencsmtp1
.ecindex IIDencsmtp2
for every possible target server. It also scales (slightly) better than having to maintain on an SMTP
client a copy of the standard CAs bundle. It also means not having to pay a CA for certificates.
-DANE requires a server operator to do three things: 1) run DNSSEC. This provides assurance to clients
+DANE requires a server operator to do three things:
+.olist
+Run DNSSEC. This provides assurance to clients
that DNS lookups they do for the server have not been tampered with. The domain MX record applying
to this server, its A record, its TLSA record and any associated CNAME records must all be covered by
DNSSEC.
-2) add TLSA DNS records. These say what the server certificate for a TLS connection should be.
-3) offer a server certificate, or certificate chain, in TLS connections which is is anchored by one of the TLSA records.
+.next
+Add TLSA DNS records. These say what the server certificate for a TLS connection should be.
+.next
+Offer a server certificate, or certificate chain, in TLS connections which is is anchored by one of the TLSA records.
+.endlist
There are no changes to Exim specific to server-side operation of DANE.
Support for client-side operation of DANE can be included at compile time by defining SUPPORT_DANE=yes
in &_Local/Makefile_&.
If it has been included, the macro "_HAVE_DANE" will be defined.
+.subsection "DNS records"
A TLSA record consist of 4 fields, the "Certificate Usage", the
"Selector", the "Matching type", and the "Certificate Association Data".
For a detailed description of the TLSA record see
This means no MD5 and no SHA-1. SHA2-256 is the minimum for reliable
interoperability (and probably the maximum too, in 2018).
+.subsection "Interaction with OCSP"
The use of OCSP-stapling should be considered, allowing for fast revocation of certificates (which would otherwise
be limited by the DNS TTL on the TLSA records). However, this is likely to only be usable with DANE-TA. NOTE: the
default of requesting OCSP for all hosts is modified iff DANE is in use, to:
those who use &%hosts_require_ocsp%&, should consider the interaction with DANE in their OCSP settings.
+.subsection "Client configuration"
For client-side DANE there are three new smtp transport options, &%hosts_try_dane%&, &%hosts_require_dane%&
and &%dane_require_tls_ciphers%&.
The &"require"& variant will result in failure if the target host is not
The router and transport option &%dnssec_request_domains%& must not be
set to &"never"&, and &%dnssec_require_domains%& is ignored.
+.subsection Observability
If verification was successful using DANE then the "CV" item in the delivery log line will show as "CV=dane".
There is a new variable &$tls_out_dane$& which will have "yes" if
The &$event_data$& will be one of the Result Types defined in
Section 4.3 of that document.
+.subsection General
Under GnuTLS, DANE is only supported from version 3.0.0 onwards.
DANE is specified in published RFCs and decouples certificate authority trust
selection from a "race to the bottom" of "you must trust everything for mail
-to get through". There is an alternative technology called MTA-STS, which
+to get through".
+There is an alternative technology called MTA-STS, which
instead publishes MX trust anchor information on an HTTPS website. At the
time this text was last updated, MTA-STS was still a draft, not yet an RFC.
Exim has no support for MTA-STS as a client, but Exim mail server operators
testing as possible at RCPT time.
-.section "The non-SMTP ACLs" "SECID190"
+.subsection "The non-SMTP ACLs" SECID190
.cindex "non-SMTP messages" "ACLs for"
The non-SMTP ACLs apply to all non-interactive incoming messages, that is, they
apply to batched SMTP as well as to non-SMTP messages. (Batched SMTP is not
temporary error for these kinds of message.
-.section "The SMTP connect ACL" "SECID191"
+.subsection "The SMTP connect ACL" SECID191
.cindex "SMTP" "connection, ACL for"
.oindex &%smtp_banner%&
The ACL test specified by &%acl_smtp_connect%& happens at the start of an SMTP
the message override the banner message that is otherwise specified by the
&%smtp_banner%& option.
-.new
For tls-on-connect connections, the ACL is run after the TLS connection
is accepted (however, &%host_reject_connection%& is tested before).
-.wen
-.section "The EHLO/HELO ACL" "SECID192"
+.subsection "The EHLO/HELO ACL" SECID192
.cindex "EHLO" "ACL for"
.cindex "HELO" "ACL for"
The ACL test specified by &%acl_smtp_helo%& happens when the client issues an
an EHLO response.
-.section "The DATA ACLs" "SECID193"
+.subsection "The DATA ACLs" SECID193
.cindex "DATA" "ACLs for"
Two ACLs are associated with the DATA command, because it is two-stage
command, with two responses being sent to the client.
the &%acl_smtp_dkim%&
and the &%acl_smtp_mime%& ACLs.
-.section "The SMTP DKIM ACL" "SECTDKIMACL"
+.subsection "The SMTP DKIM ACL" SECTDKIMACL
The &%acl_smtp_dkim%& ACL is available only when Exim is compiled with DKIM support
enabled (which is the default).
For details on the operation of DKIM, see section &<<SECDKIM>>&.
-.section "The SMTP MIME ACL" "SECID194"
+.subsection "The SMTP MIME ACL" SECID194
The &%acl_smtp_mime%& option is available only when Exim is compiled with the
content-scanning extension. For details, see chapter &<<CHAPexiscan>>&.
This ACL is evaluated after &%acl_smtp_dkim%& but before &%acl_smtp_data%&.
-.section "The SMTP PRDR ACL" "SECTPRDRACL"
+.subsection "The SMTP PRDR ACL" SECTPRDRACL
.cindex "PRDR" "ACL for"
.oindex "&%prdr_enable%&"
The &%acl_smtp_data_prdr%& ACL is available only when Exim is compiled
If the ACL is not defined, processing completes as if
the feature was not requested by the client.
-.section "The QUIT ACL" "SECTQUITACL"
+.subsection "The QUIT ACL" SECTQUITACL
.cindex "QUIT, ACL for"
The ACL for the SMTP QUIT command is anomalous, in that the outcome of the ACL
does not affect the response code to QUIT, which is always 221. Thus, the ACL
connection is closed. In these special cases, the QUIT ACL does not run.
-.section "The not-QUIT ACL" "SECTNOTQUITACL"
+.subsection "The not-QUIT ACL" SECTNOTQUITACL
.vindex &$acl_smtp_notquit$&
The not-QUIT ACL, specified by &%acl_smtp_notquit%&, is run in most cases when
an SMTP session ends without sending QUIT. However, when Exim itself is in bad
with &`-d`&, with the output going to a new logfile in the usual logs directory,
by default called &'debuglog'&.
-.new
+Logging set up by the control will be maintained across spool residency.
+
Options are a slash-separated list.
If an option takes an argument, the option name and argument are separated by
an equals character.
Several options are supported:
-.wen
.display
tag=<&'suffix'&> The filename can be adjusted with thise option.
The argument, which may access any variables already defined,
.cindex "domain" "ACL checking"
.cindex "&ACL;" "testing a recipient domain"
.vindex "&$domain_data$&"
-This condition is relevant only after a RCPT command. It checks that the domain
+This condition is relevant only in a RCPT ACL. It checks that the domain
of the recipient address is in the domain list. If percent-hack processing is
enabled, it is done before this test is done. If the check succeeds with a
lookup, the result of the lookup is placed in &$domain_data$& until the next
.cindex "local part" "ACL checking"
.cindex "&ACL;" "testing a local part"
.vindex "&$local_part_data$&"
-This condition is relevant only after a RCPT command. It checks that the local
+This condition is relevant only in a RCPT ACL. It checks that the local
part of the recipient address is in the list. If percent-hack processing is
enabled, it is done before this test. If the check succeeds with a lookup, the
result of the lookup is placed in &$local_part_data$&, which remains set until
.cindex "&%recipients%& ACL condition"
.cindex "recipient" "ACL checking"
.cindex "&ACL;" "testing a recipient"
-This condition is relevant only after a RCPT command. It checks the entire
+This condition is relevant only in a RCPT ACL. It checks the entire
recipient address against a list of recipients.
.vitem &*regex&~=&~*&<&'list&~of&~regular&~expressions'&>
non-SMTP ACLs. It causes the incoming message to be scanned for a match with
any of the regular expressions. For details, see chapter &<<CHAPexiscan>>&.
-.new
.vitem &*seen&~=&~*&<&'parameters'&>
-.cindex "&%sseen%& ACL condition"
+.cindex "&%seen%& ACL condition"
This condition can be used to test if a situation has been previously met,
for example for greylisting.
Details are given in section &<<SECTseen>>&.
-.wen
.vitem &*sender_domains&~=&~*&<&'domain&~list'&>
.cindex "&%sender_domains%& ACL condition"
(which is the most common usage), because it prevents a DNS failure from
blocking mail. However, you can change this behaviour by putting one of the
following special items in the list:
-.display
-&`+include_unknown `& behave as if the item is on the list
-&`+exclude_unknown `& behave as if the item is not on the list (default)
-&`+defer_unknown `& give a temporary error
-.endd
+.itable none 0 0 2 25* left 75* left
+.irow "+include_unknown" "behave as if the item is on the list"
+.irow "+exclude_unknown" "behave as if the item is not on the list (default)"
+.irow "+defer_unknown " "give a temporary error"
+.endtable
.cindex "&`+include_unknown`&"
.cindex "&`+exclude_unknown`&"
.cindex "&`+defer_unknown`&"
-.section "Specifying the IP address for a DNS list lookup" "SECID201"
+.subsection "Specifying the IP address for a DNS list lookup" SECID201
.cindex "DNS list" "keyed by explicit IP address"
By default, the IP address that is used in a DNS list lookup is the IP address
of the calling host. However, you can specify another IP address by listing it
-.section "DNS lists keyed on domain names" "SECID202"
+.subsection "DNS lists keyed on domain names" SECID202
.cindex "DNS list" "keyed by domain name"
There are some lists that are keyed on domain names rather than inverted IP
addresses (see, e.g., the &'domain based zones'& link at
-.section "Multiple explicit keys for a DNS list" "SECTmulkeyfor"
+.subsection "Multiple explicit keys for a DNS list" SECTmulkeyfor
.cindex "DNS list" "multiple keys for"
The syntax described above for looking up explicitly-defined values (either
names or IP addresses) in a DNS blacklist is a simplification. After the domain
-.section "Data returned by DNS lists" "SECID203"
+.subsection "Data returned by DNS lists" SECID203
.cindex "DNS list" "data returned from"
DNS lists are constructed using address records in the DNS. The original RBL
just used the address 127.0.0.1 on the right hand side of each record, but the
RBL+ list and some other lists use a number of values with different meanings.
The values used on the RBL+ list are:
-.display
-127.1.0.1 RBL
-127.1.0.2 DUL
-127.1.0.3 DUL and RBL
-127.1.0.4 RSS
-127.1.0.5 RSS and RBL
-127.1.0.6 RSS and DUL
-127.1.0.7 RSS and DUL and RBL
-.endd
+.itable none 0 0 2 20* left 80* left
+.irow 127.1.0.1 "RBL"
+.irow 127.1.0.2 "DUL"
+.irow 127.1.0.3 "DUL and RBL"
+.irow 127.1.0.4 "RSS"
+.irow 127.1.0.5 "RSS and RBL"
+.irow 127.1.0.6 "RSS and DUL"
+.irow 127.1.0.7 "RSS and DUL and RBL"
+.endtable
Section &<<SECTaddmatcon>>& below describes how you can distinguish between
different values. Some DNS lists may return more than one address record;
see section &<<SECThanmuldnsrec>>& for details of how they are checked.
returned values outside the 127/8 region.
-.section "Variables set from DNS lists" "SECID204"
+.subsection "Variables set from DNS lists" SECID204
.cindex "expansion" "variables, set from DNS list"
.cindex "DNS list" "variables set from"
.vindex "&$dnslist_domain$&"
-.section "Additional matching conditions for DNS lists" "SECTaddmatcon"
+.subsection "Additional matching conditions for DNS lists" SECTaddmatcon
.cindex "DNS list" "matching specific returned data"
You can add an equals sign and an IP address after a &%dnslists%& domain name
in order to restrict its action to DNS records with a matching right hand side.
-.section "Negated DNS matching conditions" "SECID205"
+.subsection "Negated DNS matching conditions" SECID205
You can supply a negative list of IP addresses as part of a &%dnslists%&
condition. Whereas
.code
-.section "Handling multiple DNS records from a DNS list" "SECThanmuldnsrec"
+.subsection "Handling multiple DNS records from a DNS list" SECThanmuldnsrec
A DNS lookup for a &%dnslists%& condition may return more than one DNS record,
thereby providing more than one IP address. When an item in a &%dnslists%& list
is followed by &`=`& or &`&&`& and a list of IP addresses, in order to restrict
-.section "Detailed information from merged DNS lists" "SECTmordetinf"
+.subsection "Detailed information from merged DNS lists" SECTmordetinf
.cindex "DNS list" "information from merged"
When the facility for restricting the matching IP values in a DNS list is used,
the text from the TXT record that is set in &$dnslist_text$& may not reflect
-.section "DNS lists and IPv6" "SECTmorednslistslast"
+.subsection "DNS lists and IPv6" SECTmorednslistslast
.cindex "IPv6" "DNS black lists"
.cindex "DNS list" "IPv6 usage"
If Exim is asked to do a dnslist lookup for an IPv6 address, it inverts it
.endd
-.new
.section "Previously seen user and hosts" "SECTseen"
-.cindex "&%sseen%& ACL condition"
+.cindex "&%seen%& ACL condition"
.cindex greylisting
The &%seen%& ACL condition can be used to test whether a
situation has been previously met.
It uses a hints database to record a timestamp against a key.
-host. The syntax of the condition is:
+The syntax of the condition is:
.display
-&`seen =`& <&'time interval'&> &`/`& <&'options'&>
+&`seen =`& <&'optional flag'&><&'time interval'&> &`/`& <&'options'&>
.endd
For example,
.endd
in a RCPT ACL will implement simple greylisting.
-The parameters for the condition
-are an interval followed, slash-separated, by a list of options.
+The parameters for the condition are
+a possible minus sign,
+then an interval,
+then, slash-separated, a list of options.
The interval is taken as an offset before the current time,
and used for the test.
If the interval is preceded by a minus sign then the condition returns
If a &%write%& option is given then
a record create or update is always done.
An update is done if the test is for &"since"&.
+If none of those hold and there was no existing record,
+a record is created.
Creates and updates are marked with the current time.
Note that &"seen"& should be added to the list of hints databases
for maintenance if this ACL condition is used.
-.wen
.section "Rate limiting incoming messages" "SECTratelimiting"
the &%count=%& option.
-.section "Ratelimit options for what is being measured" "ratoptmea"
+.subsection "Ratelimit options for what is being measured" ratoptmea
.cindex "rate limiting" "per_* options"
-The &%per_conn%& option limits the client's connection rate. It is not
+.vlist
+.vitem per_conn
+.cindex "rate limiting" per_conn
+This option limits the client's connection rate. It is not
normally used in the &%acl_not_smtp%&, &%acl_not_smtp_mime%&, or
&%acl_not_smtp_start%& ACLs.
-The &%per_mail%& option limits the client's rate of sending messages. This is
+.vitem per_mail
+.cindex "rate limiting" per_conn
+This option limits the client's rate of sending messages. This is
the default if none of the &%per_*%& options is specified. It can be used in
&%acl_smtp_mail%&, &%acl_smtp_rcpt%&, &%acl_smtp_predata%&, &%acl_smtp_mime%&,
&%acl_smtp_data%&, or &%acl_not_smtp%&.
-The &%per_byte%& option limits the sender's email bandwidth. It can be used in
+.vitem per_byte
+.cindex "rate limiting" per_conn
+This option limits the sender's email bandwidth. It can be used in
the same ACLs as the &%per_mail%& option, though it is best to use this option
in the &%acl_smtp_mime%&, &%acl_smtp_data%& or &%acl_not_smtp%& ACLs; if it is
used in an earlier ACL, Exim relies on the SIZE parameter given by the client
follow the limit &'m'& in the configuration with K, M, or G to specify limits
in kilobytes, megabytes, or gigabytes, respectively.
-The &%per_rcpt%& option causes Exim to limit the rate at which recipients are
+.vitem per_rcpt
+.cindex "rate limiting" per_rcpt
+This option causes Exim to limit the rate at which recipients are
accepted. It can be used in the &%acl_smtp_rcpt%&, &%acl_smtp_predata%&,
&%acl_smtp_mime%&, or &%acl_smtp_data%& ACLs. In
&%acl_smtp_rcpt%& the rate is updated one recipient at a time; in the other
in either case the rate limiting engine will see a message with many
recipients as a large high-speed burst.
-The &%per_addr%& option is like the &%per_rcpt%& option, except it counts the
+.vitem per_addr
+.cindex "rate limiting" per_addr
+This option is like the &%per_rcpt%& option, except it counts the
number of different recipients that the client has sent messages to in the
last time period. That is, if the client repeatedly sends messages to the same
recipient, its measured rate is not increased. This option can only be used in
&%acl_smtp_rcpt%&.
-The &%per_cmd%& option causes Exim to recompute the rate every time the
+.vitem per_cmd
+.cindex "rate limiting" per_cmd
+This option causes Exim to recompute the rate every time the
condition is processed. This can be used to limit the rate of any SMTP
command. If it is used in multiple ACLs it can limit the aggregate rate of
multiple different commands.
-The &%count=%& option can be used to alter how much Exim adds to the client's
-measured rate. For example, the &%per_byte%& option is equivalent to
-&`per_mail/count=$message_size`&. If there is no &%count=%& option, Exim
+.vitem count
+.cindex "rate limiting" count
+This option can be used to alter how much Exim adds to the client's
+measured rate.
+A value is required, after an equals sign.
+For example, the &%per_byte%& option is equivalent to
+&`per_mail/count=$message_size`&.
+If there is no &%count=%& option, Exim
increases the measured rate by one (except for the &%per_rcpt%& option in ACLs
-other than &%acl_smtp_rcpt%&). The count does not have to be an integer.
+other than &%acl_smtp_rcpt%&).
+The count does not have to be an integer.
-The &%unique=%& option is described in section &<<ratoptuniq>>& below.
+.vitem unique
+.cindex "rate limiting" unique
+This option is described in section &<<ratoptuniq>>& below.
+.endlist
-.section "Ratelimit update modes" "ratoptupd"
+.subsection "Ratelimit update modes" ratoptupd
.cindex "rate limiting" "reading data without updating"
You can specify one of three options with the &%ratelimit%& condition to
control when its database is updated. This section describes the &%readonly%&
next section) so you must specify the &%readonly%& option explicitly.
-.section "Ratelimit options for handling fast clients" "ratoptfast"
+.subsection "Ratelimit options for handling fast clients" ratoptfast
.cindex "rate limiting" "strict and leaky modes"
If a client's average rate is greater than the maximum, the rate limiting
engine can react in two possible ways, depending on the presence of the
.endd
-.section "Limiting the rate of different events" "ratoptuniq"
+.subsection "Limiting the rate of different events" ratoptuniq
.cindex "rate limiting" "counting unique events"
The &%ratelimit%& &%unique=%& option controls a mechanism for counting the
rate of different events. For example, the &%per_addr%& option uses this
as intended.
-.section "Using rate limiting" "useratlim"
+.subsection "Using rate limiting" useratlim
Exim's other ACL facilities are used to define what counter-measures are taken
when the rate limit is exceeded. This might be anything from logging a warning
(for example, while measuring existing sending rates in order to define
clients when the SMTP PIPELINING extension is in use. The flushing can be
disabled by using a &%control%& modifier to set &%no_callout_flush%&.
+.cindex "tainted data" "de-tainting"
+.cindex "de-tainting" "using recipient verify"
+A recipient callout which gets a 2&'xx'& code
+will assign untainted values to the
+&$domain_data$& and &$local_part_data$& variables,
+corresponding to the domain and local parts of the recipient address.
+
-.section "Additional parameters for callouts" "CALLaddparcall"
+.subsection "Additional parameters for callouts" CALLaddparcall
.cindex "callout" "additional parameters for"
The &%callout%& option can be followed by an equals sign and a number of
optional parameters, separated by commas. For example:
-.section "Callout caching" "SECTcallvercache"
+.subsection "Callout caching" SECTcallvercache
.cindex "hints database" "callout cache"
.cindex "callout" "cache, description of"
.cindex "caching" "callout"
entire domain (for example, that it accepts the local part &'postmaster'&).
When an original callout fails, a detailed SMTP error message is given about
-the failure. However, for subsequent failures use the cache data, this message
+the failure. However, for subsequent failures that use the cache data, this message
is not available.
The expiry times for negative and positive address cache records are
.vitem &*header_line&~*header_last*&
A pointer to the last of the header lines.
-.new
.vitem &*const&~uschar&~*headers_charset*&
The value of the &%headers_charset%& configuration option.
-.wen
.vitem &*BOOL&~host_checking*&
This variable is TRUE during a host checking session that is initiated by the
.vitem &*int&~lss_match_domain(uschar&~*domain,&~uschar&~*list)*&
This function checks for a match in a domain list. Domains are always
matched caselessly. The return value is one of the following:
-.display
-&`OK `& match succeeded
-&`FAIL `& match failed
-&`DEFER `& match deferred
-.endd
+.itable none 0 0 2 15* left 85* left
+.irow &`OK`& "match succeeded"
+.irow &`FAIL`& "match failed"
+.irow &`DEFER`& "match deferred"
+.endtable
DEFER is usually caused by some kind of lookup defer, such as the
inability to contact a database.
is done. If a message fails to be completely delivered at the first attempt,
the system filter is run again at the start of every retry.
If you want your filter to do something only once per message, you can make use
+.cindex retry condition
of the &%first_delivery%& condition in an &%if%& command in the filter to
prevent it happening on retries.
-.section "Resent- header lines" "SECID220"
+.section "Header lines"
+.subsection "Resent- header lines" SECID220
.chindex Resent-
RFC 2822 makes provision for sets of header lines starting with the string
&`Resent-`& to be added to a message when it is resent by the original
-.section "The Auto-Submitted: header line" "SECID221"
+.subsection Auto-Submitted: SECID221
Whenever Exim generates an autoreply, a bounce, or a delay warning message, it
includes the header line:
.code
Auto-Submitted: auto-replied
.endd
-.section "The Bcc: header line" "SECID222"
+.subsection Bcc: SECID222
.cindex "&'Bcc:'& header line"
If Exim is called with the &%-t%& option, to take recipient addresses from a
message's header, it removes any &'Bcc:'& header line that may exist (after
existing &'Bcc:'& is not removed.
-.section "The Date: header line" "SECID223"
+.subsection Date: SECID223
.cindex Date:
If a locally-generated or submission-mode message has no &'Date:'& header line,
Exim adds one, using the current date and time, unless the
&%suppress_local_fixups%& control has been specified.
-.section "The Delivery-date: header line" "SECID224"
+.subsection Delivery-date: SECID224
.cindex "&'Delivery-date:'& header line"
.oindex "&%delivery_date_remove%&"
&'Delivery-date:'& header lines are not part of the standard RFC 2822 header
messages.
-.section "The Envelope-to: header line" "SECID225"
+.subsection Envelope-to: SECID225
.chindex Envelope-to:
.oindex "&%envelope_to_remove%&"
&'Envelope-to:'& header lines are not part of the standard RFC 2822 header set.
messages.
-.section "The From: header line" "SECTthefrohea"
+.subsection From: SECTthefrohea
.chindex From:
.cindex "Sendmail compatibility" "&""From""& line"
.cindex "message" "submission"
name as described in section &<<SECTconstr>>&.
-.section "The Message-ID: header line" "SECID226"
+.subsection Message-ID: SECID226
.chindex Message-ID:
.cindex "message" "submission"
.oindex "&%message_id_header_text%&"
&%message_id_header_domain%& options.
-.section "The Received: header line" "SECID227"
+.subsection Received: SECID227
.chindex Received:
A &'Received:'& header line is added at the start of every message. The
contents are defined by the &%received_header_text%& configuration option, and
-H spool file is written) the earliest time at which delivery could start.
-.section "The References: header line" "SECID228"
+.subsection References: SECID228
.chindex References:
Messages created by the &(autoreply)& transport include a &'References:'&
header line. This is constructed according to the rules that are described in
-.section "The Return-path: header line" "SECID229"
+.subsection Return-path: SECID229
.chindex Return-path:
.oindex "&%return_path_remove%&"
&'Return-path:'& header lines are defined as something an MTA may insert when
-.section "The Sender: header line" "SECTthesenhea"
+.subsection Sender: SECTthesenhea
.cindex "&'Sender:'& header line"
.cindex "message" "submission"
.chindex Sender:
-.section "Errors in outgoing SMTP" "SECToutSMTPerr"
+.subsection "Errors in outgoing SMTP" SECToutSMTPerr
.cindex "error" "in outgoing SMTP"
.cindex "SMTP" "errors in outgoing"
.cindex "host" "error"
Exim can be configured to verify addresses in incoming SMTP commands as they
are received. See chapter &<<CHAPACL>>& for details. It can also be configured
to rewrite addresses at this time &-- before any syntax checking is done. See
-section &<<SECTrewriteS>>&.
+section &<<SSECTrewriteS>>&.
Exim can also be configured to limit the rate at which a client host submits
MAIL and RCPT commands in a single SMTP session. See the
-.section "Unrecognized SMTP commands" "SECID234"
+.subsection "Unrecognized SMTP commands" SECID234
.cindex "SMTP" "unrecognized commands"
If Exim receives more than &%smtp_max_unknown_commands%& unrecognized SMTP
commands during a single SMTP connection, it drops the connection after sending
circumstances, a number of non-SMTP lines are sent first.
-.section "Syntax and protocol errors in SMTP commands" "SECID235"
+.subsection "Syntax and protocol errors in SMTP commands" SECID235
.cindex "SMTP" "syntax errors"
.cindex "SMTP" "protocol errors"
A syntax error is detected if an SMTP command is recognized, but there is
-.section "Use of non-mail SMTP commands" "SECID236"
+.subsection "Use of non-mail SMTP commands" SECID236
.cindex "SMTP" "non-mail commands"
The &"non-mail"& SMTP commands are those other than MAIL, RCPT, and
DATA. Exim counts such commands, and drops the connection if there are too
-.section "The VRFY and EXPN commands" "SECID237"
+.subsection "The VRFY and EXPN commands" SECID237
When Exim receives a VRFY or EXPN command on a TCP/IP connection, it
runs the ACL specified by &%acl_smtp_vrfy%& or &%acl_smtp_expn%& (as
appropriate) in order to decide whether the command should be accepted or not.
than a verification (the &%-bv%& option). If an unqualified local part is given
as the argument to EXPN, it is qualified with &%qualify_domain%&. Rejections
of VRFY and EXPN commands are logged on the main and reject logs, and
-VRFY verification failures are logged on the main log for consistency with
+VRFY verification failures are logged in the main log for consistency with
RCPT failures.
-.section "The ETRN command" "SECTETRN"
+.subsection "The ETRN command" SECTETRN
.cindex "ETRN" "processing"
.cindex "ESMTP extensions" ETRN
RFC 1985 describes an ESMTP command called ETRN that is designed to
&"syslog"&. This means that an empty item in &%log_file_path%& can be used to
mean &"use the path specified at build time"&. If no such item exists, log
files are written in the &_log_& subdirectory of the spool directory. This is
-equivalent to the setting:
+equivalent to the configuration file setting:
.code
log_file_path = $spool_directory/log/%slog
.endd
A log file path may also contain &`%D`& or &`%M`& if datestamped log filenames
are in use &-- see section &<<SECTdatlogfil>>& below.
-Here are some examples of possible settings:
+Here are some examples of possible Makefile settings:
.display
&`LOG_FILE_PATH=syslog `& syslog only
&`LOG_FILE_PATH=:syslog `& syslog and default path
successful, unsuccessful, and delayed delivery. These lines can readily be
picked out by the distinctive two-character flags that immediately follow the
timestamp. The flags are:
-.display
-&`<=`& message arrival
-&`(=`& message fakereject
-&`=>`& normal message delivery
-&`->`& additional address in same delivery
-&`>>`& cutthrough message delivery
-&`*>`& delivery suppressed by &%-N%&
-&`**`& delivery failed; address bounced
-&`==`& delivery deferred; temporary problem
-.endd
+.itable none 0 0 2 10* left 90* left
+.irow &%<=%& "message arrival"
+.irow &%(=%& "message fakereject"
+.irow &%=>%& "normal message delivery"
+.irow &%->%& "additional address in same delivery"
+.irow &%>>%& "cutthrough message delivery"
+.irow &%*>%& "delivery suppressed by &%-N%&"
+.irow &%**%& "delivery failed; address bounced"
+.irow &%==%& "delivery deferred; temporary problem"
+.endtable
.section "Logging message reception" "SECID251"
.endd
The list of optional log items is in the following table, with the default
selection marked by asterisks:
-.display
-&` 8bitmime `& received 8BITMIME status
-&`*acl_warn_skipped `& skipped &%warn%& statement in ACL
-&` address_rewrite `& address rewriting
-&` all_parents `& all parents in => lines
-&` arguments `& command line arguments
-&`*connection_reject `& connection rejections
-&`*delay_delivery `& immediate delivery delayed
-&` deliver_time `& time taken to attempt delivery
-&` delivery_size `& add &`S=`&&'nnn'& to => lines
-&`*dkim `& DKIM verified domain on <= lines
-&` dkim_verbose `& separate full DKIM verification result line, per signature
-&`*dnslist_defer `& defers of DNS list (aka RBL) lookups
-&` dnssec `& DNSSEC secured lookups
-&`*etrn `& ETRN commands
-&`*host_lookup_failed `& as it says
-&` ident_timeout `& timeout for ident connection
-&` incoming_interface `& local interface on <= and => lines
-&` incoming_port `& remote port on <= lines
-&`*lost_incoming_connection `& as it says (includes timeouts)
-&` millisec `& millisecond timestamps and RT,QT,DT,D times
-&`*msg_id `& on <= lines, Message-ID: header value
-&` msg_id_created `& on <= lines, Message-ID: header value when one had to be added
-&` outgoing_interface `& local interface on => lines
-&` outgoing_port `& add remote port to => lines
-&`*queue_run `& start and end queue runs
-&` queue_time `& time on queue for one recipient
-&`*queue_time_exclusive `& exclude recieve time from QT times
-&` queue_time_overall `& time on queue for whole message
-&` pid `& Exim process id
-&` pipelining `& PIPELINING use, on <= and => lines
-&` proxy `& proxy address on <= and => lines
-&` receive_time `& time taken to receive message
-&` received_recipients `& recipients on <= lines
-&` received_sender `& sender on <= lines
-&`*rejected_header `& header contents on reject log
-&`*retry_defer `& &"retry time not reached"&
-&` return_path_on_delivery `& put return path on => and ** lines
-&` sender_on_delivery `& add sender to => lines
-&`*sender_verify_fail `& sender verification failures
-&`*size_reject `& rejection because too big
-&`*skip_delivery `& delivery skipped in a queue run
-&`*smtp_confirmation `& SMTP confirmation on => lines
-&` smtp_connection `& incoming SMTP connections
-&` smtp_incomplete_transaction`& incomplete SMTP transactions
-&` smtp_mailauth `& AUTH argument to MAIL commands
-&` smtp_no_mail `& session with no MAIL commands
-&` smtp_protocol_error `& SMTP protocol errors
-&` smtp_syntax_error `& SMTP syntax errors
-&` subject `& contents of &'Subject:'& on <= lines
-&`*tls_certificate_verified `& certificate verification status
-&`*tls_cipher `& TLS cipher suite on <= and => lines
-&` tls_peerdn `& TLS peer DN on <= and => lines
-&` tls_resumption `& append * to cipher field
-&` tls_sni `& TLS SNI on <= lines
-&` unknown_in_list `& DNS lookup failed in list match
-
-&` all `& all of the above
-.endd
+.itable none 0 0 3 2.8in left 10pt center 3in left
+.irow &`8bitmime`& "received 8BITMIME status"
+.irow &`acl_warn_skipped`& * "skipped &%warn%& statement in ACL"
+.irow &`address_rewrite`& "address rewriting"
+.irow &`all_parents`& "all parents in => lines"
+.irow &`arguments`& "command line arguments"
+.irow &`connection_reject`& * "connection rejections"
+.irow &`delay_delivery`& * "immediate delivery delayed"
+.irow &`deliver_time`& "time taken to attempt delivery"
+.irow &`delivery_size`& "add &`S=`&&'nnn'& to => lines"
+.irow &`dkim`& * "DKIM verified domain on <= lines"
+.irow &`dkim_verbose`& "separate full DKIM verification result line, per signature"
+.irow &`dnslist_defer`& * "defers of DNS list (aka RBL) lookups"
+.irow &`dnssec`& "DNSSEC secured lookups"
+.irow &`etrn`& * "ETRN commands"
+.irow &`host_lookup_failed`& * "as it says"
+.irow &`ident_timeout`& "timeout for ident connection"
+.irow &`incoming_interface`& "local interface on <= and => lines"
+.irow &`incoming_port`& "remote port on <= lines"
+.irow &`lost_incoming_connection`& * "as it says (includes timeouts)"
+.irow &`millisec`& "millisecond timestamps and RT,QT,DT,D times"
+.irow &`msg_id`& * "on <= lines, Message-ID: header value"
+.irow &`msg_id_created`& "on <= lines, Message-ID: header value when one had to be added"
+.irow &`outgoing_interface`& "local interface on => lines"
+.irow &`outgoing_port`& "add remote port to => lines"
+.irow &`queue_run`& * "start and end queue runs"
+.irow &`queue_time`& "time on queue for one recipient"
+.irow &`queue_time_exclusive`& "exclude recieve time from QT times"
+.irow &`queue_time_overall`& "time on queue for whole message"
+.irow &`pid`& "Exim process id"
+.irow &`pipelining`& "PIPELINING use, on <= and => lines"
+.irow &`proxy`& "proxy address on <= and => lines"
+.irow &`receive_time`& "time taken to receive message"
+.irow &`received_recipients`& "recipients on <= lines"
+.irow &`received_sender`& "sender on <= lines"
+.irow &`rejected_header`& * "header contents on reject log"
+.irow &`retry_defer`& * "&<quote>&retry time not reached&</quote>&"
+.irow &`return_path_on_delivery`& "put return path on => and ** lines"
+.irow &`sender_on_delivery`& "add sender to => lines"
+.irow &`sender_verify_fail`& * "sender verification failures"
+.irow &`size_reject`& * "rejection because too big"
+.irow &`skip_delivery`& * "delivery skipped in a queue run"
+.irow &`smtp_confirmation`& * "SMTP confirmation on => lines"
+.irow &`smtp_connection`& "incoming SMTP connections"
+.irow &`smtp_incomplete_transaction`& "incomplete SMTP transactions"
+.irow &`smtp_mailauth`& "AUTH argument to MAIL commands"
+.irow &`smtp_no_mail`& "session with no MAIL commands"
+.irow &`smtp_protocol_error`& "SMTP protocol errors"
+.irow &`smtp_syntax_error`& "SMTP syntax errors"
+.irow &`subject`& "contents of &'Subject:'& on <= lines"
+.irow &`tls_certificate_verified`& * "certificate verification status"
+.irow &`tls_cipher`& * "TLS cipher suite on <= and => lines"
+.irow &`tls_peerdn`& "TLS peer DN on <= and => lines"
+.irow &`tls_resumption`& "append * to cipher field"
+.irow &`tls_sni`& "TLS SNI on <= lines"
+.irow &`unknown_in_list`& "DNS lookup failed in list match"
+.irow &`all`& "&*all of the above*&"
+.endtable
See also the &%slow_lookup_log%& main configuration option,
section &<<SECID99>>&
the field has a minus appended.
.cindex "pipelining" "early connection"
-If Exim is built with the SUPPORT_PIPE_CONNECT build option
+If Exim is built without the DISABLE_PIPE_CONNECT build option
accept "L" fields have a period appended if the feature was
offered but not used, or an asterisk appended if used.
Delivery "L" fields have an asterisk appended if used.
system configuration options that configure exactly how &'exiwhat'& works. If
it doesn't seem to be working for you, check the following compile-time
options:
-.display
-&`EXIWHAT_PS_CMD `& the command for running &'ps'&
-&`EXIWHAT_PS_ARG `& the argument for &'ps'&
-&`EXIWHAT_EGREP_ARG `& the argument for &'egrep'& to select from &'ps'& output
-&`EXIWHAT_KILL_ARG `& the argument for the &'kill'& command
-.endd
+.itable none 0 0 2 30* left 70* left
+.irow &`EXIWHAT_PS_CMD`& "the command for running &'ps'&"
+.irow &`EXIWHAT_PS_ARG`& "the argument for &'ps'&"
+.irow &`EXIWHAT_EGREP_ARG`& "the argument for &'egrep'& to select from &'ps'& output"
+.irow &`EXIWHAT_KILL_ARG`& "the argument for the &'kill'& command"
+.endtable
An example of typical output from &'exiwhat'& is
.code
164 daemon: -q1h, listening on port 25
.endlist
There is one more option, &%-h%&, which outputs a list of options.
-.new
At least one selection option, or either the &*-c*& or &*-h*& option, must be given.
-.wen
.cindex "&'exim_dumpdb'&"
The entire contents of a database are written to the standard output by the
&'exim_dumpdb'& program,
-.new
taking as arguments the spool and database names.
-An option &'-z'& may be given to regest times in UTC;
+An option &'-z'& may be given to request times in UTC;
otherwise times are in the local timezone.
-.wen
+An option &'-k'& may be given to dump only the record keys.
For example, to dump the retry database:
.code
exim_dumpdb /var/spool/exim retry
sequence of digit pairs for year, month, day, hour, and minute. Colons can be
used as optional separators.
-.new
Both displayed and input times are in the local timezone by default.
If an option &'-z'& is used on the command line, displayed times
are in UTC.
-.wen
start of the epoch. The second number is a count of the number of messages
warning of delayed delivery that have been sent to the sender.
-.new
There follow a number of lines starting with a hyphen.
These contain variables, can appear in any
order, and are omitted when not relevant.
The following word specifies a variable,
and the remainder of the item depends on the variable.
-.wen
.vlist
.vitem "&%-acl%&&~<&'number'&>&~<&'length'&>"
senders).
-.section "Signing outgoing messages" "SECDKIMSIGN"
-.cindex "DKIM" "signing"
+.subsection "Signing outgoing messages" SECDKIMSIGN
+.cindex DKIM signing
For signing to be usable you must have published a DKIM record in DNS.
Note that RFC 8301 (which does not cover EC keys) says:
After expansion, this can be a list.
Each element in turn,
lowercased,
+.vindex "&$dkim_domain$&"
is put into the &%$dkim_domain%& expansion variable
while expanding the remaining signing options.
If it is empty after expansion, DKIM signing is not done,
This sets the key selector string.
After expansion, which can use &$dkim_domain$&, this can be a list.
Each element in turn is put in the expansion
+.vindex "&$dkim_selector$&"
variable &%$dkim_selector%& which may be used in the &%dkim_private_key%&
option along with &%$dkim_domain%&.
If the option is empty after expansion, DKIM signing is not done for this domain,
RFC 6376 lists these tags as RECOMMENDED.
-.section "Verifying DKIM signatures in incoming mail" "SECDKIMVFY"
-.cindex "DKIM" "verification"
+.subsection "Verifying DKIM signatures in incoming mail" SECDKIMVFY
+.cindex DKIM verification
Verification of DKIM signatures in SMTP incoming email is done for all
messages for which an ACL control &%dkim_disable_verify%& has not been set.
-.section "SRS (Sender Rewriting Scheme)" SECTSRS
+.subsection "SRS (Sender Rewriting Scheme)" SECTSRS
.cindex SRS "sender rewriting scheme"
SRS can be used to modify sender addresses when forwarding so that
encoded.
The second argument should be given as the envelope sender address before this
encoding operation.
+If this value is empty the the expansion result will be empty.
The third argument should be the recipient domain of the message when
it arrived at this system.
.endlist
that headers will be in /usr/local/include, and that the libraries
are in /usr/local/lib.
-. subsection
+.subsection Configuration SSECDMARCCONFIG
+.cindex DMARC configuration
There are three main-configuration options:
.cindex DMARC "configuration options"
the dsn_from option, and <> is used for the
envelope from.
-. I wish we had subsections...
-
+.subsection Controls SSECDMARCCONTROLS
.cindex DMARC controls
+
By default, the DMARC processing will run for any remote,
non-authenticated user. It makes sense to only verify DMARC
status of messages coming from remote, untrusted sources. You can
There are no options to either control. Both must appear before
the DATA acl.
-. subsection
+.subsection ACL SSECDMARCACL
+.cindex DMARC "ACL condition"
-DMARC checks cam be run on incoming SMTP messages by using the
+DMARC checks can be run on incoming SMTP messages by using the
&"dmarc_status"& ACL condition in the DATA ACL. You are required to
call the &"spf"& condition first in the ACLs, then the &"dmarc_status"&
condition. Putting this condition in the ACLs is required in order
right-hand side. These strings describe recommended action based
on the DMARC check. To understand what the policy recommendations
mean, refer to the DMARC website above. Valid strings are:
-.display
-&'accept '& The DMARC check passed and the library recommends accepting the email.
-&'reject '& The DMARC check failed and the library recommends rejecting the email.
-&'quarantine '& The DMARC check failed and the library recommends keeping it for further inspection.
-&'none '& The DMARC check passed and the library recommends no specific action, neutral.
-&'norecord '& No policy section in the DMARC record for this RFC5322.From field
-&'nofrom '& Unable to determine the domain of the sender.
-&'temperror '& Library error or dns error.
-&'off '& The DMARC check was disabled for this email.
-.endd
+.itable none 0 0 2 20* left 80* left
+.irow &'accept'& "The DMARC check passed and the library recommends accepting the email"
+.irow &'reject'& "The DMARC check failed and the library recommends rejecting the email"
+.irow &'quarantine'& "The DMARC check failed and the library recommends keeping it for further inspection"
+.irow &'none'& "The DMARC check passed and the library recommends no specific action, neutral"
+.irow &'norecord'& "No policy section in the DMARC record for this RFC5322.From field"
+.irow &'nofrom'& "Unable to determine the domain of the sender"
+.irow &'temperror'& "Library error or dns error"
+.irow &'off'& "The DMARC check was disabled for this email"
+.endtable
You can prefix each string with an exclamation mark to invert its
meaning, for example "!accept" will match all results but
"accept". The string list is evaluated left-to-right in a
is any error, including no DMARC record.
.endlist
-. subsection
+.subsection Logging SSECDMARCLOGGING
+.cindex DMARC logging
By default, Exim's DMARC configuration is intended to be
non-intrusive and conservative. To facilitate this, Exim will not
enable sending DMARC forensic reports
.endlist
-. subsection
+.subsection Example SSECDMARCEXAMPLE
+.cindex DMARC example
Example usage:
.code
The following expansion variables are usable
(&"internal"& and &"external"& here refer to the interfaces
of the proxy):
-.display
-&'proxy_external_address '& IP of host being proxied or IP of remote interface of proxy
-&'proxy_external_port '& Port of host being proxied or Port on remote interface of proxy
-&'proxy_local_address '& IP of proxy server inbound or IP of local interface of proxy
-&'proxy_local_port '& Port of proxy server inbound or Port on local interface of proxy
-&'proxy_session '& boolean: SMTP connection via proxy
-.endd
+.itable none 0 0 2 30* left 70* left
+.irow $proxy_external_address "IP of host being proxied or IP of remote interface of proxy"
+.irow $proxy_external_port "Port of host being proxied or Port on remote interface of proxy"
+.irow $proxy_local_address "IP of proxy server inbound or IP of local interface of proxy"
+.irow $proxy_local_port "Port of proxy server inbound or Port on local interface of proxy"
+.irow $proxy_session "boolean: SMTP connection via proxy"
+.endtable
If &$proxy_session$& is set but &$proxy_external_address$& is empty
there was a protocol error.
The variables &$sender_host_address$& and &$sender_host_port$&
Options are a string <name>=<value>.
The list of options is in the following table:
-.display
-&'auth '& authentication method
-&'name '& authentication username
-&'pass '& authentication password
-&'port '& tcp port
-&'tmo '& connection timeout
-&'pri '& priority
-&'weight '& selection bias
-.endd
+.itable none 0 0 2 10* left 90* left
+.irow &'auth'& "authentication method"
+.irow &'name'& "authentication username"
+.irow &'pass'& "authentication password"
+.irow &'port'& "tcp port"
+.irow &'tmo'& "connection timeout"
+.irow &'pri'& "priority"
+.irow &'weight'& "selection bias"
+.endtable
More details on each of these options follows:
but could be used for any message.
If a value is appended it may be:
-.display
-&`1 `& mandatory downconversion
-&`0 `& no downconversion
-&`-1 `& if SMTPUTF8 not supported by destination host
-.endd
+.itable none 0 0 2 5* right 95* left
+.irow &`1`& "mandatory downconversion"
+.irow &`0`& "no downconversion"
+.irow &`-1`& "if SMTPUTF8 not supported by destination host"
+.endtable
If no value is given, 1 is used.
If mua_wrapper is set, the utf8_downconvert control
The name is placed in the variable &$event_name$& and the event action
expansion must check this, as it will be called for every possible event type.
-.new
The current list of events is:
-.display
-&`dane:fail after transport `& per connection
-&`msg:complete after main `& per message
-&`msg:defer after transport `& per message per delivery try
-&`msg:delivery after transport `& per recipient
-&`msg:rcpt:host:defer after transport `& per recipient per host
-&`msg:rcpt:defer after transport `& per recipient
-&`msg:host:defer after transport `& per host per delivery try; host errors
-&`msg:fail:delivery after transport `& per recipient
-&`msg:fail:internal after main `& per recipient
-&`tcp:connect before transport `& per connection
-&`tcp:close after transport `& per connection
-&`tls:cert before both `& per certificate in verification chain
-&`tls:fail:connect after main `& per connection
-&`smtp:connect after transport `& per connection
-&`smtp:ehlo after transport `& per connection
-.endd
-.wen
+.itable all 0 0 4 25* left 10* center 15* center 50* left
+.row auth:fail after both "per driver per authentication attempt"
+.row dane:fail after transport "per connection"
+.row msg:complete after main "per message"
+.row msg:defer after transport "per message per delivery try"
+.row msg:delivery after transport "per recipient"
+.row msg:rcpt:host:defer after transport "per recipient per host"
+.row msg:rcpt:defer after transport "per recipient"
+.row msg:host:defer after transport "per host per delivery try; host errors"
+.row msg:fail:delivery after transport "per recipient"
+.row msg:fail:internal after main "per recipient"
+.row tcp:connect before transport "per connection"
+.row tcp:close after transport "per connection"
+.row tls:cert before both "per certificate in verification chain"
+.row tls:fail:connect after main "per connection"
+.row smtp:connect after transport "per connection"
+.row smtp:ehlo after transport "per connection"
+.endtable
New event types may be added in future.
The event name is a colon-separated list, defining the type of
An additional variable, &$event_data$&, is filled with information varying
with the event type:
-.display
-&`dane:fail `& failure reason
-&`msg:defer `& error string
-&`msg:delivery `& smtp confirmation message
-&`msg:fail:internal `& failure reason
-&`msg:fail:delivery `& smtp error message
-&`msg:host:defer `& error string
-&`msg:rcpt:host:defer `& error string
-&`msg:rcpt:defer `& error string
-&`tls:cert `& verification chain depth
-&`tls:fail:connect `& error string
-&`smtp:connect `& smtp banner
-&`smtp:ehlo `& smtp ehlo response
-.endd
+.itable all 0 0 2 20* left 80* left
+.row auth:fail "smtp response"
+.row dane:fail "failure reason"
+.row msg:defer "error string"
+.row msg:delivery "smtp confirmation message"
+.row msg:fail:internal "failure reason"
+.row msg:fail:delivery "smtp error message"
+.row msg:host:defer "error string"
+.row msg:rcpt:host:defer "error string"
+.row msg:rcpt:defer "error string"
+.row tls:cert "verification chain depth"
+.row tls:fail:connect "error string"
+.row smtp:connect "smtp banner"
+.row smtp:ehlo "smtp ehlo response"
+.endtable
The :defer events populate one extra variable: &$event_defer_errno$&.
-For complex operations an ACL expansion can be used in &%event_action%&
+For complex operations an ACL expansion can be used in &%event_action%&,
however due to the multiple contexts that Exim operates in during
the course of its processing:
.ilist
The expansion of the event_action option should normally
return an empty string. Should it return anything else the
following will be forced:
-.display
-&`tcp:connect `& do not connect
-&`tls:cert `& refuse verification
-&`smtp:connect `& close connection
-.endd
+.itable all 0 0 2 20* left 80* left
+.row auth:fail "log information to write"
+.row tcp:connect "do not connect"
+.row tls:cert "refuse verification"
+.row smtp:connect "close connection"
+.endtable
All other message types ignore the result string, and
no other use is made of it.
git://git.exim.org / exim.git / blobdiff