.set I " "
.macro copyyear
-2013
+2014
.endmacro
. /////////////////////////////////////////////////////////////////////////////
&`fail`& keyword causes a &'forced expansion failure'& &-- see section
&<<SECTforexpfai>>& for an explanation of what this means.
-The supported DNS record types are A, CNAME, MX, NS, PTR, SPF, SRV, and TXT,
+The supported DNS record types are A, CNAME, MX, NS, PTR, SPF, SRV, TLSA and TXT,
and, when Exim is compiled with IPv6 support, AAAA (and A6 if that is also
configured). If no type is given, TXT is assumed. When the type is PTR,
the data can be an IP address, written as normal; inversion and the addition of
.cindex "expansion" "case forcing"
.cindex "&%uc%& expansion item"
This forces the letters in the string into upper-case.
+
+.vitem &*${utf8clean:*&<&'string'&>&*}*&
+.cindex "correction of invalid utf-8 sequences in strings"
+.cindex "utf-8" "utf-8 sequences"
+.cindex "incorrect utf-8"
+.cindex "expansion" "utf-8 forcing"
+.cindex "&%utf8clean%& expansion item"
+This replaces any invalid utf-8 sequence in the string by the character &`?`&.
.endlist
.cindex "&%bool%& expansion condition"
This condition turns a string holding a true or false representation into
a boolean state. It parses &"true"&, &"false"&, &"yes"& and &"no"&
-(case-insensitively); also positive integer numbers map to true if non-zero,
+(case-insensitively); also integer numbers map to true if non-zero,
false if zero.
An empty string is treated as false.
Leading and trailing whitespace is ignored;
It is likely that you will need to coerce DNSSEC support on in the resolver
library, by setting:
.code
-dns_use_dnssec = 1
+dns_dnssec_ok = 1
.endd
Exim does not perform DNSSEC validation itself, instead leaving that to a
.row &%disable_ipv6%& "do no IPv6 processing"
.row &%dns_again_means_nonexist%& "for broken domains"
.row &%dns_check_names_pattern%& "pre-DNS syntax check"
+.row &%dns_dnssec_ok%& "parameter for resolver"
.row &%dns_ipv4_lookup%& "only v4 lookup for these domains"
.row &%dns_retrans%& "parameter for resolver"
.row &%dns_retry%& "parameter for resolver"
-.row &%dns_use_dnssec%& "parameter for resolver"
.row &%dns_use_edns0%& "parameter for resolver"
.row &%hold_domains%& "hold delivery for these domains"
.row &%local_interfaces%& "for routing checks"
reversed and looked up in the reverse DNS, as described in more detail in
section &<<SECTverifyCSA>>&.
+
+.option dns_dnssec_ok main integer -1
+.cindex "DNS" "resolver options"
+.cindex "DNS" "DNSSEC"
+If this option is set to a non-negative number then Exim will initialise the
+DNS resolver library to either use or not use DNSSEC, overriding the system
+default. A value of 0 coerces DNSSEC off, a value of 1 coerces DNSSEC on.
+
+If the resolver library does not support DNSSEC then this option has no effect.
+
+
.option dns_ipv4_lookup main "domain list&!!" unset
.cindex "IPv6" "DNS lookup for AAAA records"
.cindex "DNS" "IPv6 lookup for AAAA records"
See &%dns_retrans%& above.
-.option dns_use_dnssec main integer -1
-.cindex "DNS" "resolver options"
-.cindex "DNS" "DNSSEC"
-If this option is set to a non-negative number then Exim will initialise the
-DNS resolver library to either use or not use DNSSEC, overriding the system
-default. A value of 0 coerces DNSSEC off, a value of 1 coerces DNSSEC on.
-
-If the resolver library does not support DNSSEC then this option has no effect.
-
-
.option dns_use_edns0 main integer -1
.cindex "DNS" "resolver options"
.cindex "DNS" "EDNS0"
in clear.
+.option tls_try_verify_hosts smtp "host list&!! unset
+.cindex "TLS" "server certificate verification"
+.cindex "certificate" "verification of server"
+This option gives a list of hosts for which, on encrypted connections,
+certificate verification will be tried but need not succeed.
+The &%tls_verify_certificates%& option must also be set.
+
+
.option tls_verify_certificates smtp string&!! unset
.cindex "TLS" "server certificate verification"
.cindex "certificate" "verification of server"
&$host_address$& are set to the name and address of the server during the
expansion of this option. See chapter &<<CHAPTLS>>& for details of TLS.
+For back-compatability,
+if neither tls_verify_hosts nor tls_try_verify_hosts are set
+and certificate verification fails the TLS connection is closed.
+
+
+.option tls_verify_hosts smtp "host list&!! unset
+.cindex "TLS" "server certificate verification"
+.cindex "certificate" "verification of server"
+This option gives a list of hosts for which. on encrypted connections,
+certificate verification must succeed.
+The &%tls_verify_certificates%& option must also be set.
+If both this option and &%tls_try_verify_hosts%& are unset
+operation is as if this option selected all hosts.
+
expected server certificates. The client verifies the server's certificate
against this collection, taking into account any revoked certificates that are
in the list defined by &%tls_crl%&.
+Failure to verify fails the TLS connection unless either of the
+&%tls_verify_hosts%& or &%tls_try_verify_hosts%& options are set.
+
+The &%tls_verify_hosts%& and &%tls_try_verify_hosts%& options restrict
+certificate verification to the listed servers. Verification either must
+or need not succeed respectively.
If
&%tls_require_ciphers%& is set on the &(smtp)& transport, it must contain a
from one SMTP connection to another. If a recipient-verify callout connection is
requested in the same ACL it is held open and used for the data, otherwise one is made
after the ACL completes.
-Note that routers are used in verify mode.
+
+Note that routers are used in verify mode,
+and cannot depend on content of received headers.
+Note also that headers cannot be
+modified by any of the post-data ACLs (DATA, MIME and DKIM).
+Headers may be modified by routers (subject to the above) and transports.
+
+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.
Should the ultimate destination system positively accept or reject the mail,
a corresponding indication is given to the source system and nothing is queued.
Delivery in this mode avoids the generation of a bounce mail to a (possibly faked)
sender when the destination system is doing content-scan based rejection.
-Cutthrough delivery is not supported via transport-filters.
.vitem &*control&~=&~debug/*&<&'options'&>
add_header = X-blacklisted-at: $dnslist_domain
.endd
The &%add_header%& modifier is permitted in the MAIL, RCPT, PREDATA, DATA,
-MIME, and non-SMTP ACLs (in other words, those that are concerned with
+MIME, DKIM, and non-SMTP ACLs (in other words, those that are concerned with
receiving a message). The message must ultimately be accepted for
&%add_header%& to have any significant effect. You can use &%add_header%& with
any ACL verb, including &%deny%& (though this is potentially useful only in a
RCPT ACL).
+Headers will not be added to the message if the modifier is used in
+DATA, MIME or DKIM ACLs for messages delivered by cutthrough routing.
+
Leading and trailing newlines are removed from
the data for the &%add_header%& modifier; if it then
contains one or more newlines that
remove_header = x-route-mail1 : x-route-mail2
.endd
The &%remove_header%& modifier is permitted in the MAIL, RCPT, PREDATA, DATA,
-MIME, and non-SMTP ACLs (in other words, those that are concerned with
+MIME, DKIM, and non-SMTP ACLs (in other words, those that are concerned with
receiving a message). The message must ultimately be accepted for
&%remove_header%& to have any significant effect. You can use &%remove_header%&
with any ACL verb, including &%deny%&, though this is really not useful for
any verb that doesn't result in a delivered message.
+Headers will not be removed to the message if the modifier is used in
+DATA, MIME or DKIM ACLs for messages delivered by cutthrough routing.
+
More than one header can be removed at the same time by using a colon separated
list of header names. The header matching is case insensitive. Wildcards are
not permitted, nor is list expansion performed, so you cannot use hostlists to
send email. Details of how this works are given in section
&<<SECTverifyCSA>>&.
+.new
+.vitem &*verify&~=&~header_names_ascii*&
+.cindex "&%verify%& ACL condition"
+.cindex "&ACL;" "verifying header names only ASCII"
+.cindex "header lines" "verifying header names only ASCII"
+.cindex "verifying" "header names only ASCII"
+This condition is relevant only in an ACL that is run after a message has been
+received, that is, in an ACL specified by &%acl_smtp_data%& or
+&%acl_not_smtp%&. It checks all header names (not the content) to make sure
+there are no non-ASCII characters, also excluding control characters. The
+allowable characters are decimal ASCII values 33 through 126.
+
+Exim itself will handle headers with non-ASCII characters, but it can cause
+problems for downstream applications, so this option will allow their
+detection and rejection in the DATA ACL's.
+.wen
+
.vitem &*verify&~=&~header_sender/*&<&'options'&>
.cindex "&%verify%& ACL condition"
.cindex "&ACL;" "verifying sender in the header"
dnslists = some.list.example
.endd
+If an explicit key is being used for a DNS lookup and it may be an IPv6
+address you should specify alternate list separators for both the outer
+(DNS list name) list and inner (lookup keys) list:
+.code
+ dnslists = <; dnsbl.example.com/<|$acl_m_addrslist
+.endd
+
.section "Rate limiting incoming messages" "SECTratelimiting"
.cindex "rate limiting" "client sending"
.cindex "limiting client sending rates"
&%hosts%& setting, the transport's hosts are used. If an &(smtp)& transport has
&%hosts_override%& set, its hosts are always used, whether or not the router
supplies a host list.
+Callouts are only supported on &(smtp)& transports.
The port that is used is taken from the transport, if it is specified and is a
remote transport. (For routers that do verification only, no transport need be
.endd
You can safely omit this option (the default value is 1).
+.vitem &%sock%&
+.cindex "virus scanners" "simple socket-connected"
+This is a general-purpose way of talking to simple scanner daemons
+running on the local machine.
+There are four options:
+an address (which may be an IP addres and port, or the path of a Unix socket),
+a commandline to send (may include a single %s which will be replaced with
+the path to the mail file to be scanned),
+an RE to trigger on from the returned data,
+an RE to extract malware_name from the returned data.
+For example:
+.code
+av_scanner = sock:127.0.0.1 6001:%s:(SPAM|VIRUS):(.*)\$
+.endd
+Default for the socket specifier is &_/tmp/malware.sock_&.
+Default for the commandline is &_%s\n_&.
+Both regular-expressions are required.
+
.vitem &%sophie%&
.cindex "virus scanners" "Sophos and Sophie"
Sophie is a daemon that uses Sophos' &%libsavi%& library to scan for viruses.
&`R `& on &`<=`& lines: reference for local bounce
&` `& on &`=>`& &`**`& and &`==`& lines: router name
&`S `& size of message
+&`SNI `& server name indication from TLS client hello
&`ST `& shadow transport name
&`T `& on &`<=`& lines: message subject (topic)
&` `& on &`=>`& &`**`& and &`==`& lines: transport name
.next
.cindex "log" "smtp confirmation"
.cindex "SMTP" "logging confirmation"
-&%smtp_confirmation%&: The response to the final &"."& in the SMTP dialogue for
+.cindex "LMTP" "logging confirmation"
+&%smtp_confirmation%&: The response to the final &"."& in the SMTP or LMTP dialogue for
outgoing messages is added to delivery log lines in the form &`C=`&<&'text'&>.
A number of MTAs (including Exim) return an identifying string in this
response.
Exim's DKIM implementation allows to
.olist
Sign outgoing messages: This function is implemented in the SMTP transport.
-It can co-exist with all other Exim features, including transport filters.
+It can co-exist with all other Exim features
+(including transport filters)
+except cutthrough delivery.
.next
Verify signatures in incoming messages: This is implemented by an additional
ACL (acl_smtp_dkim), which can be called several times per message, with
Verification of DKIM signatures in incoming email is implemented via the
&%acl_smtp_dkim%& ACL. By default, this ACL is called once for each
syntactically(!) correct signature in the incoming message.
+A missing ACL definition defaults to accept.
+If any ACL call does not acccept, the message is not accepted.
+If a cutthrough delivery was in progress for the message it is
+summarily dropped (having wasted the transmission effort).
To evaluate the signature in the ACL a large number of expansion variables
containing the signature status and its details are set up during the
git://git.exim.org / exim.git / blobdiff