. Update the Copyright year (only) when changing content.
. /////////////////////////////////////////////////////////////////////////////
-.set previousversion "4.85"
+.set previousversion "4.86"
.include ./local_params
.set ACL "access control lists (ACLs)"
waiting for it by the time it recovers, and sending them in a single SMTP
connection is clearly beneficial. Whenever a delivery to a remote host is
deferred,
-.cindex "hints database"
+.cindex "hints database" "deferred deliveries"
Exim makes a note in its hints database, and whenever a successful
SMTP delivery has happened, it looks to see if any other messages are waiting
for the same host. If any are found, they are sent over the same SMTP
currently seen as the mainstream. Another record type called A6 was proposed
as better than AAAA because it had more flexibility. However, it was felt to be
over-complex, and its status was reduced to &"experimental"&.
-.new
Exim used to
have a compile option for including A6 record support but this has now been
withdrawn.
-.wen
.cindex "symbolic link" "to source files"
Symbolic links to relevant source files are installed in the build directory.
-&*Warning*&: The &%-j%& (parallel) flag must not be used with &'make'&; the
-building process fails if it is set.
-
If this is the first time &'make'& has been run, it calls a script that builds
a make file inside the build directory, using the configuration files from the
&_Local_& directory. The new make file is then passed to another instance of
.code
mysql_servers = <value not displayable>
.endd
-If &%configure_file%& is given as an argument, the name of the run time
-configuration file is output.
+If &%config%& is given as an argument, the config is
+output, as it was parsed, any include file resolved, any comment removed.
+
+If &%config_file%& is given as an argument, the name of the run time
+configuration file is output. (&%configure_file%& works too, for
+backward compatibility.)
If a list of configuration files was supplied, the value that is output here
is the name of the file that was actually used.
by Exim in conjunction with the &%-MC%& option. It signifies that the
connection to the remote host has been authenticated.
-.new
.vitem &%-MCD%&
.oindex "&%-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.
-.wen
.vitem &%-MCP%&
.oindex "&%-MCP%&"
This option is interpreted by Sendmail to cause debug information to be sent
to the named file. It is ignored by Exim.
-.new
.vitem &%-z%&&~<&'log-line'&>
.oindex "&%-z%&"
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,
under most shells.
-.wen
.endlist
.ecindex IIDclo1
Exim's configuration file is divided into a number of different parts. General
option settings must always appear at the start of the file. The other parts
are all optional, and may appear in any order. Each part other than the first
-is introduced by the word &"begin"& followed by the name of the part. The
-optional parts are:
+is introduced by the word &"begin"& followed by at least one literal
+space, and the name of the part. The optional parts are:
.ilist
&'ACL'&: Access control lists for controlling incoming SMTP mail (see chapter
show how you can specify hosts that are permitted to send unqualified sender
and recipient addresses, respectively.
-.new
The &%log_selector%& option is used to increase the detail of logging
over the default:
.code
log_selector = +smtp_protocol_error +smtp_syntax_error \
+tls_certificate_verified
.endd
-.wen
The &%percent_hack_domains%& option is also commented out:
.code
.endd
This transport is used for handling deliveries to pipes that are generated by
redirection (aliasing or users' &_.forward_& files). The &%return_output%&
-option specifies that any output generated by the pipe is to be returned to the
-sender.
+option specifies that any output on stdout or stderr generated by the pipe is to
+be returned to the sender.
.code
address_file:
driver = appendfile
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.
.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 given by the context in which the list is expanded.
.endlist
String expansions, lists, and lookups interact with each other in such a way
&`fail`& keyword causes a &'forced expansion failure'& &-- see section
&<<SECTforexpfai>>& for an explanation of what this means.
-.new
The supported DNS record types are A, CNAME, MX, NS, PTR, SOA, SPF, SRV, TLSA
and TXT, and, when Exim is compiled with IPv6 support, AAAA.
If no type is given, TXT is assumed.
-.wen
For any record type, if multiple records are found, the data is returned as a
concatenation, with newline as the default separator. The order, of course,
It is permitted to specify a space as the separator character. Further
white space is ignored.
-.new
.cindex "SOA record" "in &(dnsdb)& lookup"
For an SOA lookup, while no result is obtained the lookup is redone with
successively more leading components dropped from the given domain.
.code
${lookup dnsdb{>:,; soa=a.b.example.com}}
.endd
-.wen
.section "Dnsdb lookup modifiers" "SECTdnsdb_mod"
.cindex "dnsdb modifiers"
See also the &$lookup_dnssec_authenticated$& variable.
-.new
.cindex timeout "dns lookup"
.cindex "DNS" timeout
Timeout for the dnsdb lookup can be controlled by a retrans modifier.
Retries for the dnsdb lookup can be controlled by a retry modifier.
The form if &"retry_VAL"& where VAL is an integer.
The default count is set by the main configuration option &%dns_retry%&.
+
+.new
+.cindex cacheing "of dns lookup"
+.cindex TTL "of dns lookup"
+.cindex DNS TTL
+Dnsdb lookup results are cached within a single process (and its children).
+The cache entry lifetime is limited to the smallest time-to-live (TTL)
+value of the set of returned DNS records.
.wen
set a server-side limit on the time taken to complete a search.
The SERVERS parameter allows you to specify an alternate list of ldap servers
-to use for an individual lookup. The global ldap_servers option provides a
+to use for an individual lookup. The global &%ldap_default_servers%& option provides a
default list of ldap servers, and a single lookup can specify a single ldap
server to use. But when you need to do a lookup with a list of servers that is
different than the default list (maybe different order, maybe a completely
found, but that is still a successful query. In other words, the list of
servers provides a backup facility, not a list of different places to look.
+.new
The &%quote_mysql%&, &%quote_pgsql%&, and &%quote_oracle%& expansion operators
convert newline, tab, carriage return, and backspace to \n, \t, \r, and \b
respectively, and the characters single-quote, double-quote, and backslash
-itself are escaped with backslashes. The &%quote_pgsql%& expansion operator, in
-addition, escapes the percent and underscore characters. This cannot be done
-for MySQL because these escapes are not recognized in contexts where these
-characters are not special.
+itself are escaped with backslashes.
+.wen
.section "Specifying the server in the query" "SECTspeserque"
For MySQL and PostgreSQL lookups (but not currently for Oracle and InterBase),
different types of pattern for each case are described, but first we cover some
general facilities that apply to all four kinds of list.
-.new
Note that other parts of Exim use a &'string list'& which does not
support all the complexity available in
domain, host, address and local part lists.
-.wen
configuration, you must add &%-export-dynamic%& to EXTRALIBS.
-.new
.vitem "&*${env{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}}*&"
.cindex "expansion" "extracting value from environment"
.cindex "environment" "value from"
search failure.
If {<&'string1'&>} is omitted the search result is substituted on
search success.
-.wen
.vitem "&*${extract{*&<&'key'&>&*}{*&<&'string1'&>&*}{*&<&'string2'&>&*}&&&
Upper case and lower case letters are synonymous in header names. If the
following character is white space, the terminating colon may be omitted, but
this is not recommended, because you may then forget it when it is needed. When
-white space terminates the header name, it is included in the expanded string.
-If the message does not contain the given header, the expansion item is
-replaced by an empty string. (See the &%def%& condition in section
-&<<SECTexpcond>>& for a means of testing for the existence of a header.)
+white space terminates the header name, this white space is included in the
+expanded string. If the message does not contain the given header, the
+expansion item is replaced by an empty string. (See the &%def%& condition in
+section &<<SECTexpcond>>& for a means of testing for the existence of a
+header.)
If there is more than one header with the same name, they are all concatenated
to form the substitution string, up to a maximum length of 64K. Unless
.code
${listextract{-3}{<, x,42,99,& Mailer,,/bin/bash}{result: $value}}
.endd
-yields &"result: 99"&.
+yields &"result: 42"&.
If {<&'string3'&>} is omitted, an empty string is used for string3.
If {<&'string2'&>} is also omitted, the value that was
byte value 127 is converted to &`\x7f`&.
+.new
+.vitem &*${ipv6denorm:*&<&'string'&>&*}*&
+.cindex "&%ipv6denorm%& expansion item"
+.cindex "IP address" normalisation
+This expands an IPv6 address to a full eight-element colon-separated set
+of hex digits including leading zeroes.
+A trailing ipv4-style dotted-decimal set is converted to hex.
+Pure IPv4 addresses are converted to IPv4-mapped IPv6.
+
+.vitem &*${ipv6norm:*&<&'string'&>&*}*&
+.cindex "&%ipv6norm%& expansion item"
+.cindex "IP address" normalisation
+.cindex "IP address" "canonical form"
+This converts an IPv6 address to canonical form.
+Leading zeroes of groups are omitted, and the longest
+set of zero-valued groups is replaced with a double colon.
+A trailing ipv4-style dotted-decimal set is converted to hex.
+Pure IPv4 addresses are converted to IPv4-mapped IPv6.
+.wen
+
+
.vitem &*${lc:*&<&'string'&>&*}*&
.cindex "case forcing in strings"
.cindex "string" "case forcing"
When a &%match%& expansion condition succeeds, these variables contain the
captured substrings identified by the regular expression during subsequent
processing of the success string of the containing &%if%& expansion item.
-However, they do not retain their values afterwards; in fact, their previous
+In the expansion condition case
+they do not retain their values afterwards; in fact, their previous
values are restored at the end of processing an &%if%& item. The numerical
variables may also be set externally by some other matching process which
precedes the expansion of the string. For example, the commands available in
&$originator_uid$&). If Exim re-execs itself, this variable in the new
incarnation normally contains the Exim uid.
-.vitem &$compile_date$&
-.vindex "&$compile_date$&"
-The date on which the Exim binary was compiled.
+.vitem &$callout_address$&
+.vindex "&$callout_address$&"
+After a callout for verification, spamd or malware daemon service, the
+address that was connected to.
.vitem &$compile_number$&
.vindex "&$compile_number$&"
of times it has been compiled. This serves to distinguish different
compilations of the same version of the program.
-.new
.vitem &$config_dir$&
.vindex "&$config_dir$&"
The directory name of the main configuration file. That is, the content of
.vitem &$config_file$&
.vindex "&$config_file$&"
The name of the main configuration file Exim is using.
-.wen
.vitem &$demime_errorlevel$&
.vindex "&$demime_errorlevel$&"
content-scanning extension and the obsolete &%demime%& condition. For details,
see section &<<SECTdemimecond>>&.
-.new
.vitem &$dkim_cur_signer$& &&&
&$dkim_verify_status$& &&&
&$dkim_verify_reason$& &&&
When a message has been received this variable contains
a colon-separated list of signer domains and identities for the message.
For details see chapter &<<CHAPdkim>>&.
-.wen
.vitem &$dnslist_domain$& &&&
&$dnslist_matched$& &&&
.vindex "&$exim_uid$&"
This variable contains the numerical value of the Exim user id.
-.new
.vitem &$exim_version$&
.vindex "&$exim_version$&"
This variable contains the version string of the Exim build.
The first character is a major version number, currently 4.
Then after a dot, the next group of digits is a minor version number.
There may be other characters following the minor version.
-.wen
.vitem &$found_extension$&
.vindex "&$found_extension$&"
It will be empty if &(DNSSEC)& was not requested,
&"no"& if the result was not labelled as authenticated data
and &"yes"& if it was.
-.new
Results that are labelled as authoritative answer that match
the &%dns_trust_aa%& configuration variable count also
as authenticated data.
-.wen
.vitem &$mailstore_basename$&
.vindex "&$mailstore_basename$&"
qualified host name. See also &$smtp_active_hostname$&.
+.new
+.vitem &$prdr_requested$&
+.cindex "PRDR" "variable for"
+This variable is set to &"yes"& if PRDR was requested by the client for the
+current message, otherwise &"no"&.
+.wen
+
.vitem &$prvscheck_address$&
This variable is used in conjunction with the &%prvscheck%& expansion item,
which is described in sections &<<SECTexpansionitems>>& and
This variable is set to contain the matching regular expression after a
&%regex%& ACL condition has matched (see section &<<SECTscanregex>>&).
+.vitem "&$regex1$&, &$regex2$&, etc"
+.cindex "regex submatch variables (&$1regex$& &$2regex$& etc)"
+When a &%regex%& or &%mime_regex%& ACL condition succeeds,
+these variables contain the
+captured substrings identified by the regular expression.
+
.vitem &$reply_address$&
.vindex "&$reply_address$&"
the argument of a HELO or EHLO command. This is omitted if it is identical to
the verified host name or to the host's IP address in square brackets.
-.new
.vitem &$sender_helo_dnssec$&
.vindex "&$sender_helo_dnssec$&"
This boolean variable is true if a successful HELO verification was
.cindex "DNS" "DNSSEC"
done using DNS information the resolver library stated was authenticated data.
-.wen
.vitem &$sender_helo_name$&
.vindex "&$sender_helo_name$&"
It is only useful as the argument of a
&%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
or a &%def%& condition.
-.new
If certificate verification fails it may refer to a failing chain element
which is not the leaf.
-.wen
.vitem &$tls_out_ourcert$&
.vindex "&$tls_out_ourcert$&"
outbound connection. It is only useful as the argument of a
&%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
or a &%def%& condition.
-.new
If certificate verification fails it may refer to a failing chain element
which is not the leaf.
-.wen
.vitem &$tls_in_certificate_verified$&
.vindex "&$tls_in_certificate_verified$&"
connection, and Exim is configured to request a certificate from the client,
the value of the Distinguished Name of the certificate is made available in the
&$tls_in_peerdn$& during subsequent processing.
-.new
If certificate verification fails it may refer to a failing chain element
which is not the leaf.
-.wen
The deprecated &$tls_peerdn$& variable refers to the inbound side
except when used in the context of an outbound SMTP delivery, when it refers to
connection, and Exim is configured to request a certificate from the server,
the value of the Distinguished Name of the certificate is made available in the
&$tls_out_peerdn$& during subsequent processing.
-.new
If certificate verification fails it may refer to a failing chain element
which is not the leaf.
-.wen
.vitem &$tls_in_sni$&
.vindex "&$tls_in_sni$&"
processed and the message itself has been received, but before the final
acknowledgment is sent. See chapter &<<CHAPACL>>& for further details.
-.new
.option acl_smtp_data_prdr main string&!! accept
.cindex "PRDR" "ACL for"
.cindex "DATA" "PRDR ACL for"
.cindex "&ACL;" "PRDR-related"
.cindex "&ACL;" "per-user data processing"
-.wen
This option defines the ACL that,
if the PRDR feature has been negotiated,
is run for each recipient after an SMTP DATA command has been
processed and the message itself has been received, but before the
acknowledgment is sent. See chapter &<<CHAPACL>>& for further details.
-.new
.option acl_smtp_dkim main string&!! unset
.cindex DKIM "ACL for"
This option defines the ACL that is run for each DKIM signature
of a received message.
See chapter &<<CHAPdkim>>& for further details.
-.wen
.option acl_smtp_etrn main string&!! unset
.cindex "ETRN" "ACL for"
extension. It defines the ACL that is run for each MIME part in a message. See
section &<<SECTscanmimepart>>& for details.
-.new
.option acl_smtp_notquit main string&!! unset
.cindex "not-QUIT, ACL for"
This option defines the ACL that is run when an SMTP session
ends without a QUIT command being received.
See chapter &<<CHAPACL>>& for further details.
-.wen
.option acl_smtp_predata main string&!! unset
This option defines the ACL that is run when an SMTP DATA command is
to handle IPv6 literal addresses.
-.new
.option dkim_verify_signers main "domain list&!!" $dkim_signers
.cindex DKIM "controlling calls to the ACL"
This option gives a list of DKIM domains for which the DKIM ACL is run.
It is expanded after the message is received; by default it runs
the ACL once for each signature in the message.
See chapter &<<CHAPdkim>>&.
-.wen
.option dns_again_means_nonexist main "domain list&!!" unset
parameter values are available in the external resolver interface structure,
but nowhere does it seem to describe how they are used or what you might want
to set in them.
-.new
See also the &%slow_lookup_log%& option.
-.wen
.option dns_retry main integer 0
See &%dns_retrans%& above.
-.new
.option dns_trust_aa main "domain list&!!" unset
.cindex "DNS" "resolver options"
.cindex "DNS" "DNSSEC"
authority section is compared against the list. If the answer packet is
authoritative but the answer section is empty, the name of the first SOA
record in the authoritative section is used instead.
-.wen
.cindex "DNS" "resolver options"
.option dns_use_edns0 main integer -1
handled CR and LF characters in incoming messages. What happens now is
described in section &<<SECTlineendings>>&.
-.new
.option dsn_advertise_hosts main "host list&!!" unset
.cindex "bounce messages" "success"
.cindex "DSN" "success"
A NOTIFY=SUCCESS option requests success-DSN messages.
A NOTIFY= option with no argument requests that no delay or failure DSNs
are sent.
-.wen
.option dsn_from main "string&!!" "see below"
.cindex "&'From:'& header line" "in bounces"
. Allow this long option name to split; give it unsplit as a fifth argument
. for the automatic .oindex that is generated by .option.
-.option "extract_addresses_remove_ &~&~arguments" main boolean true &&&
+.option "extract_addresses_remove_arguments" main boolean true &&&
extract_addresses_remove_arguments
.oindex "&%-t%&"
.cindex "command line" "addresses with &%-t%&"
This option is an obsolete synonym for &%bounce_return_size_limit%&.
-.new
.option rfc1413_hosts main "host list&!!" @[]
.cindex "RFC 1413"
.cindex "host" "for RFC 1413 calls"
an item in the list.
The default value specifies just this host, being any local interface
for the system.
-.wen
-.new
.option rfc1413_query_timeout main time 0s
-.wen
.cindex "RFC 1413" "query timeout"
.cindex "timeout" "for RFC 1413 call"
This sets the timeout on RFC 1413 identification calls. If it is set to zero,
using TCP/IP), and the &%-bnq%& option was not set.
-.new
.option slow_lookup_log main integer 0
.cindex "logging" "slow lookups"
.cindex "dns" "logging slow lookups"
If the value is nonzero it is taken as a number of milliseconds
and lookups taking longer than this are logged.
Currently this applies only to DNS lookups.
-.wen
The former means that Exim was expecting to read an SMTP command; the latter
means that it was in the DATA phase, reading the contents of a message.
-.new
If the first character of the option is a &"$"& the option is
expanded before use and may depend on
&$sender_host_name$&, &$sender_host_address$& and &$sender_host_port$&.
-.wen
.oindex "&%-os%&"
unfortunately not all, operating systems.
-.option tls_advertise_hosts main "host list&!!" unset
+.new
+.option tls_advertise_hosts main "host list&!!" *
+.wen
.cindex "TLS" "advertising"
.cindex "encryption" "on SMTP connection"
.cindex "SMTP" "encrypted connection"
of the STARTTLS command to set up an encrypted session is advertised in
response to EHLO only to those client hosts that match this option. See
chapter &<<CHAPTLS>>& for details of Exim's support for TLS.
+.new
+Note that the default value requires that a certificate be supplied
+using the &%tls_certificate%& option. If no certificate is available then
+the &%tls_advertise_hosts%& option should be set empty.
+.wen
.option tls_certificate main string&!! unset
acceptable bound from 1024 to 2048.
-.new
.option tls_eccurve main string&!! prime256v1
.cindex TLS "EC cryptography"
If built with a recent-enough version of OpenSSL,
which tell the library to choose.
If the option is set to an empty string, no EC curves will be enabled.
-.wen
.option tls_ocsp_file main string&!! unset
status proof for the server's certificate, as obtained from the
Certificate Authority.
+.new
+Usable for GnuTLS 3.4.4 or 3.3.17 or OpenSSL 1.1.0 (or later).
+.wen
+
.option tls_on_connect_ports main "string list" unset
.cindex SSMTP
See &%tls_verify_hosts%& below.
-.new
.option tls_verify_certificates main string&!! system
.cindex "TLS" "client certificate verification"
.cindex "certificate" "verification of client"
explicitly
either by file or directory
are added to those given by the system default location.
-.wen
These certificates should be for the certificate authorities trusted, rather
than the public cert of individual clients. With both OpenSSL and GnuTLS, if
unless you really, really know what you are doing. See also the generic
transport option of the same name.
-.new
.option dnssec_request_domains routers "domain list&!!" unset
.cindex "MX record" "security"
.cindex "DNSSEC" "MX lookup"
the dnssec request bit set. Any returns not having the Authenticated Data bit
(AD bit) set will be ignored and logged as a host-lookup failure.
This applies to all of the SRV, MX, AAAA, A lookup sequence.
-.wen
.option domains routers&!? "domain list&!!" unset
to be used.
-.new
.option dsn_lasthop routers boolean false
.cindex "DSN" "success"
.cindex "Delivery Status Notification" "success"
Exim will not pass on DSN requests to downstream DSN-aware hosts but will
instead send a success DSN as if the next hop does not support DSN.
Not effective on redirect routers.
-.wen
.cindex "header lines" "adding"
.cindex "router" "adding header lines"
This option specifies a list of text headers,
-.new
newline-separated (by default, changeable in the usual way),
-.wen
that is associated with any addresses that are accepted by the router.
Each item is separately expanded, at routing time. However, this
option has no effect when an address is just being verified. The way in which
.cindex "header lines" "removing"
.cindex "router" "removing header lines"
This option specifies a list of text headers,
-.new
colon-separated (by default, changeable in the usual way),
-.wen
that is associated with any addresses that are accepted by the router.
Each item is separately expanded, at routing time. However, this
option has no effect when an address is just being verified. The way in which
routers, and this can lead to problems with duplicates -- see the similar
warning for &%headers_add%& above.
-.new
&*Warning 3*&: Because of the separate expansion of the list items,
items that contain a list separator must have it doubled.
To avoid this, change the list separator (&<<SECTlistsepchange>>&).
-.wen
an address; if such a router is expected to handle "all remaining non-local
domains", then it is important to set &%no_more%&.
-.new
The router will defer rather than decline if the domain
is found in the &%fail_defer_domains%& router option.
-.wen
Reasons for a &(dnslookup)& router to decline currently include:
.ilist
-.new
.option fail_defer_domains dnslookup "domain list&!!" unset
.cindex "MX record" "not found"
DNS lookups for domains matching &%fail_defer_domains%&
domain while the DNS configuration is not ready.
However, it will result in any message with mistyped domains
also being queued.
-.wen
.option mx_domains dnslookup "domain list&!!" unset
files and pipes, and for generating autoreplies. See the &%file_transport%&,
&%pipe_transport%& and &%reply_transport%& descriptions below.
-.new
If success DSNs have been requested
.cindex "DSN" "success"
.cindex "Delivery Status Notification" "success"
redirection triggers one and the DSN options are not passed any further.
-.wen
.cindex "header lines" "adding in transport"
.cindex "transport" "header lines; adding"
This option specifies a list of text headers,
-.new
newline-separated (by default, changeable in the usual way),
-.wen
which are (separately) expanded and added to the header
portion of a message as it is transported, as described in section
&<<SECTheadersaddrem>>&. Additional header lines can also be specified by
.cindex "header lines" "removing"
.cindex "transport" "header lines; removing"
This option specifies a list of header names,
-.new
colon-separated (by default, changeable in the usual way);
-.wen
these headers are omitted from the message as it is transported, as described
in section &<<SECTheadersaddrem>>&. Header removal can also be specified by
routers.
to ensure that any additional groups associated with the uid are set up.
+.new
+.option max_parallel transports integer&!! unset
+.cindex limit "transport parallelism"
+.cindex transport "parallel processes"
+.cindex transport "concurrency limit"
+.cindex "delivery" "parallelism for transport"
+If this option is set and expands to an integer greater than zero
+it limits the number of concurrent runs of the transport.
+The control does not apply to shadow transports.
+
+.cindex "hints database" "transport concurrency control"
+Exim implements this control by means of a hints database in which a record is
+incremented whenever a transport process is beaing created. The record
+is decremented and possibly removed when the process terminates.
+Obviously there is scope for
+records to get left lying around if there is a system or program crash. To
+guard against this, Exim ignores any records that are more than six hours old.
+
+If you use this option, you should also arrange to delete the
+relevant hints database whenever your system reboots. The names of the files
+start with &_misc_& and they are kept in the &_spool/db_& directory. There
+may be one or two files, depending on the type of DBM in use. The same files
+are used for ETRN and smtp transport serialization.
+.wen
+
+
.option message_size_limit transports string&!! 0
.cindex "limit" "message size per transport"
.cindex "size" "of message, limit"
This option sets up a filtering (in the Unix shell sense) process for messages
at transport time. It should not be confused with mail filtering as set up by
individual users or via a system filter.
+.new
+If unset, or expanding to an empty string, no filtering is done.
+.wen
When the message is about to be written out, the command specified by
&%transport_filter%& is started up in a separate, parallel process, and
delivery, the two pipe transports may be run concurrently. You must ensure that
any pipe commands you set up are robust against this happening. If the commands
write to a file, the &%exim_lock%& utility might be of use.
+.new
+Alternatively the &%max_parallel%& option could be used with a value
+of "1" to enforce serialization.
+.wen
&%force_command%& is set, expanding out to the original argument vector as
separate items, similarly to a Unix shell &`"$@"`& construct.
+
.option ignore_status pipe boolean false
If this option is true, the status returned by the subprocess that is set up to
run the command is ignored, and Exim behaves as if zero had been returned.
&*Note*&: This option does not apply to timeouts, which do not return a status.
See the &%timeout_defer%& option for how timeouts are handled.
+
.option log_defer_output pipe boolean false
.cindex "&(pipe)& transport" "logging output"
If this option is set, and the status returned by the command is
one of the codes listed in &%temp_errors%& (that is, delivery was deferred),
-and any output was produced, the first line of it is written to the main log.
+and any output was produced on stdout or stderr, the first line of it is
+written to the main log.
.option log_fail_output pipe boolean false
-If this option is set, and the command returns any output, and also ends with a
-return code that is neither zero nor one of the return codes listed in
-&%temp_errors%& (that is, the delivery failed), the first line of output is
-written to the main log. This option and &%log_output%& are mutually exclusive.
-Only one of them may be set.
-
+If this option is set, and the command returns any output on stdout or
+stderr, and also ends with a return code that is neither zero nor one of
+the return codes listed in &%temp_errors%& (that is, the delivery
+failed), the first line of output is written to the main log. This
+option and &%log_output%& are mutually exclusive. Only one of them may
+be set.
.option log_output pipe boolean false
-If this option is set and the command returns any output, the first line of
-output is written to the main log, whatever the return code. This option and
-&%log_fail_output%& are mutually exclusive. Only one of them may be set.
-
+If this option is set and the command returns any output on stdout or
+stderr, the first line of output is written to the main log, whatever
+the return code. This option and &%log_fail_output%& are mutually
+exclusive. Only one of them may be set.
.option max_output pipe integer 20K
Exim will not try to start a TLS session when delivering to any host that
matches this list. See chapter &<<CHAPTLS>>& for details of TLS.
-.new
.option hosts_verify_avoid_tls smtp "host list&!!" unset
.cindex "TLS" "avoiding for certain hosts"
Exim will not try to start a TLS session for a verify callout,
or when delivering in cutthrough mode,
to any host that matches this list.
-.wen
.option hosts_max_try smtp integer 5
unauthenticated. See also &%hosts_require_auth%&, and chapter
&<<CHAPSMTPAUTH>>& for details of authentication.
-.new
.option hosts_try_prdr smtp "host list&!!" *
.cindex "PRDR" "enabling, optional in client"
This option provides a list of servers to which, provided they announce
PRDR support, Exim will attempt to negotiate PRDR
for multi-recipient messages.
The option can usually be left as default.
-.wen
.option interface smtp "string list&!!" unset
.cindex "bind IP address"
&$domain$& in an expansion for the transport, because it is set only when there
is a single domain involved in a remote delivery.
-.new
It is expanded per-address and can depend on any of
&$address_data$&, &$domain_data$&, &$local_part_data$&,
&$host$&, &$host_address$& and &$host_port$&.
-.wen
.option port smtp string&!! "see below"
.cindex "port" "sending TCP/IP"
each time they connect. In this situation the use of the IP address as part of
the retry key leads to undesirable behaviour. Setting this option false causes
Exim to use only the host name.
-.new
Since it is expanded it can be made to depend on the host or domain.
-.wen
.option serialize_hosts smtp "host list&!!" unset
may be one or two files, depending on the type of DBM in use. The same files
are used for ETRN serialization.
+.new
+See also the &%max_parallel%& generic transport option.
+.wen
+
.option size_addition smtp integer 1024
.cindex "SMTP" "SIZE"
in clear.
-.new
.option tls_try_verify_hosts smtp "host list&!!" *
-.wen
.cindex "TLS" "server certificate verification"
.cindex "certificate" "verification of server"
This option gives a list of hosts for which, on encrypted connections,
certificate verification succeeds.
-.new
.option tls_verify_cert_hostnames smtp "host list&!!" *
.cindex "TLS" "server certificate hostname verification"
.cindex "certificate" "verification of server"
limited to being the initial component of a 3-or-more component FQDN.
There is no equivalent checking on client certificates.
-.wen
-.new
.option tls_verify_certificates smtp string&!! system
.cindex "TLS" "server certificate verification"
.cindex "certificate" "verification of server"
The use of a directory for the option value is not available for GnuTLS versions
preceding 3.3.6 and a single file must be used.
-.wen
With OpenSSL the certificates specified
explicitly
legitimate reasons for this (host died, network died), but if it repeats a lot
for the same host, it indicates something odd.
-.new
.vitem &%lookup%&
A DNS lookup for a host failed.
Note that a &%dnslookup%& router will need to have matched
its &%fail_defer_domains%& option for this retry type to be usable.
Also note that a &%manualroute%& router will probably need
its &%host_find_failed%& option set to &%defer%&.
-.wen
.vitem &%refused_MX%&
A connection to a host obtained from an MX record was refused.
the PLAIN authentication mechanism (RFC 2595) or the LOGIN mechanism, which is
not formally documented, but used by several MUAs. The seventh authenticator
supports Microsoft's &'Secure Password Authentication'& mechanism.
-.new
The eighth is an Exim authenticator but not an SMTP one;
instead it can use information from a TLS negotiation.
-.wen
The authenticators are configured using the same syntax as other drivers (see
section &<<SECTfordricon>>&). If no authenticators are required, no
. ////////////////////////////////////////////////////////////////////////////
. ////////////////////////////////////////////////////////////////////////////
-.new
.chapter "The tls authenticator" "CHAPtlsauth"
.scindex IIDtlsauth1 "&(tls)& authenticator"
.scindex IIDtlsauth2 "authenticators" "&(tls)&"
.endd
.ecindex IIDtlsauth1
.ecindex IIDtlsauth2
-.wen
Note that because authentication is traditionally an SMTP operation,
Exim requests a certificate as part of the setup of the TLS session. The
contents of the certificate are verified by comparing it with a list of
expected certificates.
-.new
These may be the system default set (depending on library version),
-.wen
an explicit file or,
depending on library version, a directory, identified by
&%tls_verify_certificates%&.
proof expires. The downside is that it requires server support.
Unless Exim is built with the support disabled,
-or with GnuTLS earlier than version 3.1.3,
+.new
+or with GnuTLS earlier than version 3.3.16 / 3.4.8
+.wen
support for OCSP stapling is included.
There is a global option called &%tls_ocsp_file%&.
If the &%tls_verify_certificates%& option is set on the &(smtp)& transport, it
specifies a collection of expected server certificates.
-.new
These may be the system default set (depending on library version),
-.wen
a file or,
depending on library version, a directory,
must name a file or,
PRDR may be used to support per-user content filtering. Without it
one must defer any recipient after the first that has a different
content-filter configuration. With PRDR, the RCPT-time check
-for this can be disabled when the MAIL-time $smtp_command included
-"PRDR". Any required difference in behaviour of the main DATA-time
+.new
+.cindex "PRDR" "variable for"
+for this can be disabled when the variable &$prdr_requested$&
+is &"yes"&.
+.wen
+Any required difference in behaviour of the main DATA-time
ACL should however depend on the PRDR-time ACL having run, as Exim
will avoid doing so in some situations (e.g. single-recipient mails).
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
does not in fact control any access.
-.new
For this reason, it may only accept
or warn as its final result.
-.wen
This ACL can be used for tasks such as custom logging at the end of an SMTP
session. For example, you can use ACL variables in other ACLs to count
The option is usable in the RCPT ACL.
If enabled for a message received via smtp and routed to an smtp transport,
-.new
and only one transport, interface, destination host and port combination
is used for all recipients of the message,
-.wen
then the delivery connection is made while the receiving connection is open
and data is copied from one to the other.
for a mail will be quietly ignored.
If a recipient-verify callout connection is subsequently
requested in the same ACL it is held open and used for
-.new
any subsequent recipients and the data,
-.wen
otherwise one is made after the initial RCPT ACL completes.
Note that routers are used in verify mode,
Cutthrough delivery is not supported via transport-filters or when DKIM signing
of outgoing messages is done, because it sends data to the ultimate destination
before the entire message has been received from the source.
-.new
It is not supported for messages received with the SMTP PRDR option in use.
-.wen
Should the ultimate destination system positively accept or reject the mail,
a corresponding indication is given to the source system and nothing is queued.
received, that is, in an ACL specified by &%acl_smtp_data%& or
&%acl_not_smtp%&. It checks the syntax of all header lines that can contain
lists of addresses (&'Sender:'&, &'From:'&, &'Reply-To:'&, &'To:'&, &'Cc:'&,
-and &'Bcc:'&). Unqualified addresses (local parts without domains) are
+and &'Bcc:'&), returning true if there are no problems.
+Unqualified addresses (local parts without domains) are
permitted only in locally generated messages and from hosts that match
&%sender_unqualified_hosts%& or &%recipient_unqualified_hosts%&, as
appropriate.
one of its aliases, does, when it is itself looked up in the DNS, yield the
original IP address.
-.new
There is one possible option, &`defer_ok`&. If this is present and a
DNS operation returns a temporary error, the verify condition succeeds.
-.wen
If this condition is used for a locally generated message (that is, when there
is no client host involved), it always succeeds.
warn message = X-Warn: sending host is on dialups list
dnslists = dialups.mail-abuse.org
.endd
-DNS list lookups are cached by Exim for the duration of the SMTP session,
+.cindex cacheing "of dns lookup"
+.cindex DNS TTL
+DNS list lookups are cached by Exim for the duration of the SMTP session
+.new
+(but limited by the DNS return TTL value),
+.wen
so a lookup based on the IP address is done at most once for any incoming
-connection. Exim does not share information between multiple incoming
+connection (assuming long-enough TTL).
+Exim does not share information between multiple incoming
connections (but your local name server cache should be active).
specialized interfaces for &"daemon"& type virus scanners, which are resident
in memory and thus are much faster.
-.new
A timeout of 2 minutes is applied to a scanner call (by default);
if it expires then a defer action is taken.
-.wen
.oindex "&%av_scanner%&"
You can set the &%av_scanner%& option in the main part of the configuration
The following scanner types are supported in this release:
.vlist
-.new
.vitem &%avast%&
.cindex "virus scanners" "avast"
This is the scanner daemon of Avast. It has been tested with Avast Core
SENSITIVITY
PACK
.endd
-.wen
.vitem &%aveserver%&
message.
The &%malware%& condition takes a right-hand argument that is expanded before
-.new
use and taken as a list, slash-separated by default.
-.wen
The first element can then be one of
.ilist
A regular expression, in which case the message is scanned for viruses. The
condition succeeds if a virus is found and its name matches the regular
expression. This allows you to take special actions on certain types of virus.
-.new
Note that &"/"& characters in the RE must be doubled due to the list-processing,
unless the separator is changed (in the usual way).
-.wen
.endlist
You can append a &`defer_ok`& element to the &%malware%& argument list to accept
messages even if there is a problem with the virus scanner.
Otherwise, such a problem causes the ACL to defer.
-.new
You can append a &`tmo=<val>`& element to the &%malware%& argument list to
specify a non-default timeout. The default is two minutes.
For example:
malware = * / defer_ok / tmo=10s
.endd
A timeout causes the ACL to defer.
-.wen
+
+.vindex "&$callout_address$&"
+When a connection is made to the scanner the expansion variable &$callout_address$&
+is set to record the actual address used.
.vindex "&$malware_name$&"
When a virus is found, the condition sets up an expansion variable called
.cindex "Rspamd"
The &%spam%& ACL condition calls SpamAssassin's &%spamd%& daemon to get a spam
score and a report for the message.
-.new
Support is also provided for Rspamd.
For more information about installation and configuration of SpamAssassin or
Rspamd refer to their respective websites at
&url(http://spamassassin.apache.org) and &url(http://www.rspamd.com)
-.wen
SpamAssassin can be installed with CPAN by running:
.code
spamd_address = 192.168.99.45 387
.endd
-.new
To use Rspamd (which by default listens on all local addresses
on TCP port 11333)
you should add &%variant=rspamd%& after the address/port pair, for example:
.code
spamd_address = 127.0.0.1 11333 variant=rspamd
.endd
-.wen
As of version 2.60, &%SpamAssassin%& also supports communication over UNIX
sockets. If you want to us these, supply &%spamd_address%& with an absolute
servers are tried until one succeeds. If no server responds, the &%spam%&
condition defers.
-.new
Unix and TCP socket specifications may be mixed in any order.
Each element of the list is a list itself, space-separated by default
and changeable in the usual way.
Elements after the first for Unix sockets, or second for TCP socket,
are options.
-The supported option are:
+The supported options are:
.code
pri=<priority> Selection priority
weight=<value> Selection bias
The &`retry`& option specifies a time after which a single retry for
a failed connect is made.
The default is to not retry.
-.wen
The &%spamd_address%& variable is expanded before use if it starts with
a dollar sign. In this case, the expansion may return a string that is
used as the list so that multiple spamd servers can be the result of an
expansion.
+.vindex "&$callout_address$&"
+When a connection is made to the server the expansion variable &$callout_address$&
+is set to record the actual address used.
+
.section "Calling SpamAssassin from an Exim ACL" "SECID206"
Here is a simple example of the use of the &%spam%& condition in a DATA ACL:
.code
relevant if you have set up multiple SpamAssassin profiles. If you do not want
to scan using a specific profile, but rather use the SpamAssassin system-wide
default profile, you can scan for an unknown name, or simply use &"nobody"&.
-.new
Rspamd does not use this setting. However, you must put something on the
right-hand side.
-.wen
The name allows you to use per-domain or per-user antispam profiles in
principle, but this is not straightforward in practice, because a message may
&%spam%& condition has to be called from a DATA-time ACL in order to be able to
read the contents of the message, the variables &$local_part$& and &$domain$&
are not set.
-.new
Careful enforcement of single-recipient messages
(e.g. by responding with defer in the recipient ACL for all recipients
after the first),
or the use of PRDR,
.cindex "PRDR" "use for per-user SpamAssassin profiles"
are needed to use this feature.
-.wen
The right-hand side of the &%spam%& condition is expanded before being used, so
you can put lookups or conditions there. When the right-hand side evaluates to
.cindex "spam scanning" "returned variables"
When the &%spam%& condition is run, it sets up a number of expansion
variables.
-.new
Except for &$spam_report$&,
-.wen
these variables are saved with the received message so are
available for use at delivery time.
A string consisting of a number of &"+"& or &"-"& characters, representing the
integer part of the spam score value. A spam score of 4.4 would have a
&$spam_bar$& value of &"++++"&. This is useful for inclusion in warning
-headers, since MUAs can match on such strings.
+headers, since MUAs can match on such strings. The maximum length of the
+spam bar is 50 characters.
.vitem &$spam_report$&
A multiline text table, containing the full SpamAssassin report for the
message. Useful for inclusion in headers or reject messages.
-.new
This variable is only usable in a DATA-time ACL.
-.wen
-.new
.vitem &$spam_action$&
For SpamAssassin either 'reject' or 'no action' depending on the
spam score versus threshold.
For Rspamd, the recommended action.
-.wen
.endlist
proposed filename for an attachment, if one was found in either the
&'Content-Type:'& or &'Content-Disposition:'& headers. The filename will be
RFC2047
-.new
or RFC2231
-.wen
decoded, but no additional sanity checks are done.
If no filename was
found, this variable contains the empty string.
The conditions returns true if any one of the regular expressions matches. The
&$regex_match_string$& expansion variable is then set up and contains the
matching regular expression.
+The expansion variables &$regex1$& &$regex2$& etc
+are set to any substrings captured by the regular expression.
&*Warning*&: With large messages, these conditions can be fairly
CPU-intensive.
The third item is used to introduce any text from pipe transports that is to be
returned to the sender. It is omitted if there is no such text.
.next
-.new
The fourth, fifth and sixth items will be ignored and may be empty.
The fields exist for back-compatibility
-.wen
.endlist
The default state (&%bounce_message_file%& unset) is equivalent to the
.cindex "log" "delivery line"
The format of the single-line entry in the main log that is written for every
delivery is shown in one of the examples below, for local and remote
-deliveries, respectively. Each example has been split into two lines in order
+deliveries, respectively. Each example has been split into multiple lines in order
to fit it on the page:
.code
2002-10-31 08:59:13 16ZCW1-0005MB-00 => marv
&`*etrn `& ETRN commands
&`*host_lookup_failed `& as it says
&` ident_timeout `& timeout for ident connection
-.new
&` incoming_interface `& local interface on <= and => lines
-.wen
&` incoming_port `& remote port on <= lines
&`*lost_incoming_connection `& as it says (includes timeouts)
+.new
+&` outgoing_interface `& local interface on => lines
+.wen
&` outgoing_port `& add remote port to => lines
&`*queue_run `& start and end queue runs
&` queue_time `& time on queue for one recipient
&`*size_reject `& rejection because too big
&`*skip_delivery `& delivery skipped in a queue run
&`*smtp_confirmation `& SMTP confirmation on => lines
-&` smtp_connection `& SMTP connections
+&` 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
-.new
&`*tls_certificate_verified `& certificate verification status
-.wen
&`*tls_cipher `& TLS cipher suite on <= and => lines
&` tls_peerdn `& TLS peer DN on <= and => lines
&` tls_sni `& TLS SNI on <= lines
&` all `& all of the above
.endd
+See also the &%slow_lookup_log%& main configuration option,
+section &<<SECID99>>&
+
More details on each of these items follows:
.ilist
&%incoming_interface%&: The interface on which a message was received is added
to the &"<="& line as an IP address in square brackets, tagged by I= and
followed by a colon and the port number. The local interface and port are also
-added to other SMTP log lines, for example &"SMTP connection from"& and to
-rejection lines
+added to other SMTP log lines, for example &"SMTP connection from"&, to
+rejection lines, and (despite the name) to outgoing &"=>"& and &"->"& lines.
.new
-and (despite the name) the local interface is added to &"=>"& lines..
+The latter can be disabled by turning off the &%outgoing_interface%& option.
.wen
.next
.cindex "log" "incoming remote port"
&%lost_incoming_connection%&: A log line is written when an incoming SMTP
connection is unexpectedly dropped.
.next
+.cindex "log" "outgoing interface"
+.cindex "log" "local interface"
+.cindex "log" "local address and port"
+.cindex "TCP/IP" "logging local address and port"
+.cindex "interface" "logging"
+.new
+&%outgoing_interface%&: If &%incoming_interface%& is turned on, then the
+interface on which a message was sent is added to delivery lines as an I= tag
+followed by IP address in square brackets. You can disable this by turning
+off the &%outgoing_interface%& option.
+.wen
+.next
.cindex "log" "outgoing remote port"
.cindex "port" "logging outgoint remote"
.cindex "TCP/IP" "logging ougtoing remote port"
&%outgoing_port%&: The remote port number is added to delivery log lines (those
-containing => tags) following the IP address. This option is not included in
-the default setting, because for most ordinary configurations, the remote port
-number is always 25 (the SMTP port).
+containing => tags) following the IP address.
+.new
+The local port is also added if &%incoming_interface%& and
+&%outgoing_interface%& are both enabled.
+.wen
+This option is not included in the default setting, because for most ordinary
+configurations, the remote port number is always 25 (the SMTP port), and the
+local port is a random ephemeral port.
.next
.cindex "log" "process ids in"
.cindex "pid (process id)" "in log lines"
.next
.cindex "log" "SMTP connections"
.cindex "SMTP" "logging connections"
-&%smtp_connection%&: A log line is written whenever an SMTP connection is
+&%smtp_connection%&: A log line is written whenever an incoming SMTP connection is
established or closed, unless the connection is from a host that matches
&%hosts_connection_nolog%&. (In contrast, &%lost_incoming_connection%& applies
only when the closure is unexpected.) This applies to connections from local
.next
Serializing delivery to a specific host (when &%serialize_hosts%& is set in an
&(smtp)& transport)
+.next
+Limiting the concurrency of specific transports (when &%max_parallel%& is set
+in a transport)
.endlist
git://git.exim.org / users / heiko / exim.git / blobdiff