DNS: time-limit cached returns, using TTL. Bug 1395

[users/heiko/exim.git] / doc / doc-docbook / spec.xfpt

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index 8b8a531b9dcdfedf2626b344448897e0dfb49f4b..ed3533a0c8bfd05007cc3e753c774217c146f9e4 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -6993,6 +6993,15 @@ 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
+
 
 .section "Pseudo dnsdb record types" "SECID66"
 .cindex "MX record" "in &(dnsdb)& lookup"
@@ -9390,7 +9399,7 @@ yields &"42"&, and
 .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
@@ -11319,9 +11328,10 @@ not the same as the user id of the originator of a message (see
 &$originator_uid$&). 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 "&$compile_number$&"
@@ -14467,7 +14477,7 @@ routing, but which are not used for listening by the daemon. See section
 . 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%&"
@@ -29207,9 +29217,15 @@ deny  dnslists = blackholes.mail-abuse.org
 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).
 
 
@@ -30962,6 +30978,10 @@ malware = * / defer_ok / tmo=10s
 .endd
 A timeout causes the ACL to defer.
 
+.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
 &$malware_name$& that contains the name of the virus. You can use it in a
@@ -31112,6 +31132,10 @@ 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