defined. AAAA records (analogous to A records for IPv4) are in use, and are
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"&. It is not known
-if anyone is actually using A6 records. Exim has support for A6 records, but
-this is included only if you set &`SUPPORT_A6=YES`& in &_Local/Makefile_&. The
-support has not been tested for some time.
+over-complex, and its status was reduced to &"experimental"&. Exim used to
+have a compile option for including A6 record support but this has now been
+withdrawn.
&<<SECTforexpfai>>& for an explanation of what this means.
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,
+and, when Exim is compiled with IPv6 support, AAAA.
+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
&%in-addr.arpa%& or &%ip6.arpa%& happens automatically. For example:
.code
If the data for a PTR record is not a syntactically valid IP address, it is not
altered and nothing is added.
-For any record type, if multiple records are found (or, for A6 lookups, if a
-single record leads to multiple addresses), the data is returned as a
+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,
depends on the DNS resolver. You can specify a different separator character
between multiple records by putting a right angle-bracket followed immediately
authorization required but absent, or &"?"& for unknown.
.cindex "A+" "in &(dnsdb)& lookup"
-The pseudo-type A+ performs an A6 lookup (if configured) followed by an AAAA
+The pseudo-type A+ performs an AAAA
and then an A lookup. All results are returned; defer processing
(see below) is handled separately for each lookup. Example:
.code
It is only useful as the argument of a
&%certextract%& expansion item, &%md5%&, &%sha1%& or &%sha256%& operator,
or a &%def%& condition.
+If certificate verification fails it may refer to a failing chain element
+which is not the leaf.
.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.
+If certificate verification fails it may refer to a failing chain element
+which is not the leaf.
.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.
+If certificate verification fails it may refer to a failing chain element
+which is not the leaf.
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.
+If certificate verification fails it may refer to a failing chain element
+which is not the leaf.
.vitem &$tls_in_sni$&
.vindex "&$tls_in_sni$&"
.cindex "DNS" "DNSSEC"
DNS lookups for domains matching &%dnssec_request_domains%& will be done with
the dnssec request bit set.
-This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
+This applies to all of the SRV, MX, AAAA, A lookup sequence.
DNS lookups for domains matching &%dnssec_request_domains%& will be done with
the dnssec request bit set. Any returns not having the Authenticated Data bit
(AD bit) set wil be ignored and logged as a host-lookup failure.
-This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
+This applies to all of the SRV, MX, AAAA, A lookup sequence.
.cindex "DNS" "DNSSEC"
DNS lookups for domains matching &%dnssec_request_domains%& will be done with
the dnssec request bit set.
-This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
+This applies to all of the SRV, MX, AAAA, A lookup sequence.
DNS lookups for domains matching &%dnssec_request_domains%& will be done with
the dnssec request bit set. Any returns not having the Authenticated Data bit
(AD bit) set wil be ignored and logged as a host-lookup failure.
-This applies to all of the SRV, MX A6, AAAA, A lookup sequence.
+This applies to all of the SRV, MX, AAAA, A lookup sequence.
are options.
The supported option are:
.code
-variant=rspamd Use Rspamd rather than SpamAssassin protocol
+pri=<priority> Selection priority
+weight=<value> Selection bias
time=<start>-<end> Use only between these times of day
+retry=<timespec> Retry on connect fail
tmo=<timespec> Connection time limit
-weight=<value> Selection bias
-backup Use only if all non-backup servers fail
-retry=<timespec> Retry on connect fail
+variant=rspamd Use Rspamd rather than SpamAssassin protocol
.endd
+The &`pri`& option specifies a priority for the server within the list,
+higher values being tried first.
+The deafult priority is 1.
+
+The &`weight`& option specifies a selection bias.
+Within a priority set
+servers are queried in a random fashion, weighted by this value.
+The default value for selection bias is 1.
+
Time specifications for the &`time`& option are <hour>.<minute>.<second>
in the local time zone; each element being one or more digits.
Either the seconds or both minutes and seconds, plus the leading &`.`&
characters, may be omitted and will be taken as zero.
-Timeout specifications for the &`tmo`& and &`retry`& options
+Timeout specifications for the &`retry`& and &`tmo`& options
are the usual Exim time interval standard, eg. &`20s`& or &`1m`&.
The &`tmo`& option specifies an overall timeout for communication.
The &`retry`& option specifies a time after which a single retry for
a failed connect is made.
The default is to not retry.
-
-Servers are queried in a random fashion, weighted by the selection bias.
-The default value for selection bias is 1.
.wen
The &%spamd_address%& variable is expanded before use if it starts with
&%spam%& condition has to be called from a DATA ACL in order to be able to
read the contents of the message, the variables &$local_part$& and &$domain$&
are not set.
+Careful enforcement of single-recipient messages
+(eg. 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.
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