PRDR: Introduce $prdr_requested flag variable. Bug 1712

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

diff --git a/doc/doc-docbook/spec.xfpt b/doc/doc-docbook/spec.xfpt
index c023ca4c408cd5c5f3565e839925c631258b48b0..b0b1585fe5c2e08abc4ec6c5bf1a5dd3c506ceeb 100644 (file)
--- a/doc/doc-docbook/spec.xfpt
+++ b/doc/doc-docbook/spec.xfpt
@@ -1575,7 +1575,7 @@ If a host is unreachable for a period of time, a number of messages may be
 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,
 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
 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


@@ -4800,8 +4800,8 @@ help with this. See the comments in &_src/EDITME_& for details.
 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
 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
 
 .ilist
 &'ACL'&: Access control lists for controlling incoming SMTP mail (see chapter


@@ -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%&.
 
 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"
 
 .section "Pseudo dnsdb record types" "SECID66"
 .cindex "MX record" "in &(dnsdb)& lookup"


@@ -7312,7 +7321,7 @@ The TIME parameter (also a number of seconds) is passed to the server to
 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
 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
 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


@@ -7528,13 +7537,12 @@ a query is successfully processed. The result of a query may be that no data is
 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.
 
 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
 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),
 
 .section "Specifying the server in the query" "SECTspeserque"
 For MySQL and PostgreSQL lookups (but not currently for Oracle and InterBase),


@@ -9390,7 +9398,7 @@ yields &"42"&, and
 .code
 ${listextract{-3}{<, x,42,99,& Mailer,,/bin/bash}{result: $value}}
 .endd
 .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
 
 If {<&'string3'&>} is omitted, an empty string is used for string3.
 If {<&'string2'&>} is also omitted, the value that was


@@ -11319,9 +11327,10 @@ 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.
 
 &$originator_uid$&). 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 "&$compile_number$&"
 
 .vitem &$compile_number$&
 .vindex "&$compile_number$&"


@@ -11980,6 +11989,13 @@ a single-component name, Exim calls &[gethostbyname()]& (or
 qualified host name. See also &$smtp_active_hostname$&.
 
 
 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
 .vitem &$prvscheck_address$&
 This variable is used in conjunction with the &%prvscheck%& expansion item,
 which is described in sections &<<SECTexpansionitems>>& and


@@ -20529,6 +20545,32 @@ transport, the &[initgroups()]& function is called when running the transport
 to ensure that any additional groups associated with the uid are set up.
 
 
 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"
 .option message_size_limit transports string&!! 0
 .cindex "limit" "message size per transport"
 .cindex "size" "of message, limit"


@@ -22426,6 +22468,10 @@ If two messages arrive at almost the same time, and both are routed to a pipe
 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.
 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

 
 
 
 
 
 


@@ -23608,6 +23654,10 @@ 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 serialization.
 
 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"
 
 .option size_addition smtp integer 1024
 .cindex "SMTP" "SIZE"


@@ -27350,8 +27400,12 @@ for some or all recipients.
 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
 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).
 
 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).
 


@@ -29207,9 +29261,15 @@ deny  dnslists = blackholes.mail-abuse.org
 warn  message  = X-Warn: sending host is on dialups list
       dnslists = dialups.mail-abuse.org
 .endd
 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
 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).
 
 
 connections (but your local name server cache should be active).
 
 


@@ -30962,6 +31022,10 @@ malware = * / defer_ok / tmo=10s
 .endd
 A timeout causes the ACL to defer.
 
 .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
 .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


@@ -31073,7 +31137,7 @@ In the latter case, the range is tried in strict order.
 
 Elements after the first for Unix sockets, or second for TCP socket,
 are options.
 
 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
 .code
 pri=<priority>      Selection priority
 weight=<value>      Selection bias


@@ -31112,6 +31176,10 @@ 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.
 
 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
 .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


@@ -36241,6 +36309,9 @@ Serializing ETRN runs (when &%smtp_etrn_serialize%& is set)
 .next
 Serializing delivery to a specific host (when &%serialize_hosts%& is set in an
 &(smtp)& transport)
 .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
 
 
 .endlist