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ACCESS(5)		      File Formats Manual		     ACCESS(5)

NAME
       access -	Postfix	SMTP server access table

SYNOPSIS
       postmap /usr/local/etc/postfix/access

       postmap -q "string" /usr/local/etc/postfix/access

       postmap -q - /usr/local/etc/postfix/access <inputfile

DESCRIPTION
       This  document  describes access	control	on remote SMTP client informa-
       tion: host names, network addresses, and	envelope sender	 or  recipient
       addresses;   it	is  implemented	 by  the  Postfix  SMTP	 server.   See
       header_checks(5)	or body_checks(5) for access control on	the content of
       email messages.

       Normally,  the  access(5) table is specified as a text file that	serves
       as input	to the postmap(1) command.  The	result,	an indexed file	in dbm
       or  db  format,	is used	for fast searching by the mail system. Execute
       the command "postmap /usr/local/etc/postfix/access" to rebuild  an  in-
       dexed file after	changing the corresponding text	file.

       When  the  table	 is provided via other means such as NIS, LDAP or SQL,
       the same	lookups	are done as for	ordinary indexed files.

       Alternatively, the table	can be provided	as  a  regular-expression  map
       where  patterns are given as regular expressions, or lookups can	be di-
       rected to TCP-based server. In those cases, the lookups are done	 in  a
       slightly	different way as described below under "REGULAR	EXPRESSION TA-
       BLES" or	"TCP-BASED TABLES".

CASE FOLDING
       The search string is folded to lowercase	before database	lookup.	As  of
       Postfix	2.3,  the search string	is not case folded with	database types
       such as regexp: or pcre:	whose lookup fields can	match both  upper  and
       lower case.

TABLE FORMAT
       The input format	for the	postmap(1) command is as follows:

       pattern action
	      When  pattern  matches  a	 mail address, domain or host address,
	      perform the corresponding	action.

       blank lines and comments
	      Empty lines and whitespace-only lines are	ignored, as are	 lines
	      whose first non-whitespace character is a	`#'.

       multi-line text
	      A	 logical  line	starts	with  non-whitespace text. A line that
	      starts with whitespace continues a logical line.

EMAIL ADDRESS PATTERNS
       With lookups from indexed files such as DB or DBM,  or  from  networked
       tables  such  as	 NIS,  LDAP or SQL, patterns are tried in the order as
       listed below:

       user@domain
	      Matches the specified mail address.

       domain.tld
	      Matches domain.tld as the	domain part of an email	address.

	      The pattern domain.tld also matches subdomains,  but  only  when
	      the string smtpd_access_maps is listed in	the Postfix parent_do-
	      main_matches_subdomains configuration setting.

       .domain.tld
	      Matches subdomains of  domain.tld,  but  only  when  the	string
	      smtpd_access_maps	 is  not  listed  in  the  Postfix  parent_do-
	      main_matches_subdomains configuration setting.

       user@  Matches all mail addresses with the specified user part.

       Note: lookup of the null	sender address is not possible with some types
       of lookup table.	By default, Postfix uses <> as the lookup key for such
       addresses. The value is specified with the smtpd_null_access_lookup_key
       parameter in the	Postfix	main.cf	file.

EMAIL ADDRESS EXTENSION
       When a mail address localpart contains the optional recipient delimiter
       (e.g., user+foo@domain),	the  lookup  order  becomes:  user+foo@domain,
       user@domain, domain, user+foo@, and user@.

HOST NAME/ADDRESS PATTERNS
       With  lookups  from  indexed files such as DB or	DBM, or	from networked
       tables such as NIS, LDAP	or SQL,	the following lookup patterns are  ex-
       amined in the order as listed:

       domain.tld
	      Matches domain.tld.

	      The  pattern  domain.tld	also matches subdomains, but only when
	      the string smtpd_access_maps is listed in	the Postfix parent_do-
	      main_matches_subdomains configuration setting.

       .domain.tld
	      Matches  subdomains  of  domain.tld,  but	 only  when the	string
	      smtpd_access_maps	 is  not  listed  in  the  Postfix  parent_do-
	      main_matches_subdomains configuration setting.

       net.work.addr.ess

       net.work.addr

       net.work

       net    Matches  the  specified IPv4 host	address	or subnetwork. An IPv4
	      host address is a	sequence of four decimal octets	 separated  by
	      ".".

	      Subnetworks  are	matched	 by  repeatedly	 truncating  the  last
	      ".octet" from the	remote IPv4 host address string	until a	 match
	      is found in the access table, or until further truncation	is not
	      possible.

	      NOTE 1: The access map lookup key	must be	in canonical form:  do
	      not specify unnecessary null characters, and do not enclose net-
	      work address information with "[]" characters.

	      NOTE 2: use the cidr lookup table	type to	 specify  network/net-
	      mask patterns. See cidr_table(5) for details.

       net:work:addr:ess

       net:work:addr

       net:work

       net    Matches  the  specified IPv6 host	address	or subnetwork. An IPv6
	      host address is a	sequence of three to eight  hexadecimal	 octet
	      pairs separated by ":".

	      Subnetworks  are	matched	 by  repeatedly	 truncating  the  last
	      ":octetpair" from	the remote IPv6	host address  string  until  a
	      match  is	found in the access table, or until further truncation
	      is not possible.

	      NOTE 1: the truncation and comparison are	done with  the	string
	      representation  of  the IPv6 host	address. Thus, not all the ":"
	      subnetworks will be tried.

	      NOTE 2: The access map lookup key	must be	in canonical form:  do
	      not specify unnecessary null characters, and do not enclose net-
	      work address information with "[]" characters.

	      NOTE 3: use the cidr lookup table	type to	 specify  network/net-
	      mask patterns. See cidr_table(5) for details.

	      IPv6 support is available	in Postfix 2.2 and later.

ACCEPT ACTIONS
       OK     Accept the address etc. that matches the pattern.

       all-numerical
	      An  all-numerical	result is treated as OK. This format is	gener-
	      ated by address-based relay authorization	schemes	such  as  pop-
	      before-smtp.

       For other accept	actions, see "OTHER ACTIONS" below.

REJECT ACTIONS
       Postfix	version	2.3 and	later support enhanced status codes as defined
       in RFC 3463.  When no code is specified at the beginning	 of  the  text
       below, Postfix inserts a	default	enhanced status	code of	"5.7.1"	in the
       case of reject actions, and "4.7.1" in the case of defer	 actions.  See
       "ENHANCED STATUS	CODES" below.

       4NN text

       5NN text
	      Reject  the  address  etc. that matches the pattern, and respond
	      with the numerical three-digit code and  text.  4NN  means  "try
	      again later", while 5NN means "do	not try	again".

	      The  following  responses	 have  special meaning for the Postfix
	      SMTP server:

	      421 text (Postfix	2.3 and	later)

	      521 text (Postfix	2.6 and	later)
		     After responding with the numerical three-digit code  and
		     text,  disconnect immediately from	the SMTP client.  This
		     frees up SMTP server resources so that they can  be  made
		     available to another SMTP client.

		     Note: The "521" response should be	used only with botnets
		     and other malware where interoperability is  of  no  con-
		     cern.   The "send 521 and disconnect" behavior is NOT de-
		     fined in the SMTP standard.

       REJECT optional text...
	      Reject the address etc. that matches  the	 pattern.  Reply  with
	      "$access_map_reject_code	optional  text..."  when  the optional
	      text is specified, otherwise reply with a	generic	error response
	      message.

       DEFER optional text...
	      Reject  the  address  etc.  that matches the pattern. Reply with
	      "$access_map_defer_code optional text..."	when the optional text
	      is specified, otherwise reply with a generic error response mes-
	      sage.

	      This feature is available	in Postfix 2.6 and later.

       DEFER_IF_REJECT optional	text...
	      Defer the	request	if some	later restriction would	 result	 in  a
	      REJECT action. Reply with	"$access_map_defer_code	4.7.1 optional
	      text..." when the	optional text is  specified,  otherwise	 reply
	      with a generic error response message.

	      Prior to Postfix 2.6, the	SMTP reply code	is 450.

	      This feature is available	in Postfix 2.1 and later.

       DEFER_IF_PERMIT optional	text...
	      Defer the	request	if some	later restriction would	result in a an
	      explicit or implicit PERMIT action.  Reply with "$access_map_de-
	      fer_code	4.7.1	optional  text..."  when  the optional text is
	      specified, otherwise reply with a	generic	 error	response  mes-
	      sage.

	      Prior to Postfix 2.6, the	SMTP reply code	is 450.

	      This feature is available	in Postfix 2.1 and later.

       For other reject	actions, see "OTHER ACTIONS" below.

OTHER ACTIONS
       restriction...
	      Apply   the   named  UCE	restriction(s)	(permit,  reject,  re-
	      ject_unauth_destination, and so on).

       BCC user@domain
	      Send one copy of the message to the specified recipient.

	      If multiple BCC actions are specified within the same SMTP  MAIL
	      transaction, only	the last action	will be	used.

	      This feature is not part of the stable Postfix release.

       DISCARD optional	text...
	      Claim successful delivery	and silently discard the message.  Log
	      the optional text	if specified, otherwise	log a generic message.

	      Note: this action	currently affects all recipients of  the  mes-
	      sage.   To discard only one recipient without discarding the en-
	      tire message, use	the transport(5) table to direct mail  to  the
	      discard(8) service.

	      This feature is available	in Postfix 2.0 and later.

       DUNNO  Pretend that the lookup key was not found. This prevents Postfix
	      from trying substrings of	the lookup key (such  as  a  subdomain
	      name, or a network address subnetwork).

	      This feature is available	in Postfix 2.0 and later.

       FILTER transport:destination
	      After the	message	is queued, send	the entire message through the
	      specified	external content filter. The transport name  specifies
	      the  first  field	 of  a	mail delivery agent definition in mas-
	      ter.cf; the syntax of the	next-hop destination is	 described  in
	      the  manual  page	of the corresponding delivery agent.  More in-
	      formation	about external content filters is in the Postfix  FIL-
	      TER_README file.

	      Note  1: do not use $number regular expression substitutions for
	      transport	or destination unless you know	that  the  information
	      has a trusted origin.

	      Note  2:	this  action overrides the main.cf content_filter set-
	      ting, and	affects	all recipients of the  message.	 In  the  case
	      that  multiple  FILTER  actions  fire, only the last one is exe-
	      cuted.

	      Note 3: the purpose of the FILTER	command	is to override message
	      routing.	 To  override  the  recipient's	 transport but not the
	      next-hop destination, specify an empty filter destination	(Post-
	      fix  2.7 and later), or specify a	transport:destination that de-
	      livers through a different Postfix  instance  (Postfix  2.6  and
	      earlier).	Other options are using	the recipient-dependent	trans-
	      port_maps	 or  the  sender-dependent   sender_dependent_default-
	      _transport_maps features.

	      This feature is available	in Postfix 2.0 and later.

       HOLD optional text...
	      Place  the  message  on  the hold	queue, where it	will sit until
	      someone either deletes it	or releases it for delivery.  Log  the
	      optional text if specified, otherwise log	a generic message.

	      Mail  that is placed on hold can be examined with	the postcat(1)
	      command, and can be destroyed or released	with the  postsuper(1)
	      command.

	      Note:  use  "postsuper -r" to release mail that was kept on hold
	      for  a  significant  fraction  of	  $maximal_queue_lifetime   or
	      $bounce_queue_lifetime,  or  longer. Use "postsuper -H" only for
	      mail that	will not expire	within a few delivery attempts.

	      Note: this action	currently affects all recipients of  the  mes-
	      sage.

	      This feature is available	in Postfix 2.0 and later.

       PREPEND headername: headervalue
	      Prepend  the specified message header to the message.  When more
	      than one PREPEND action executes,	the first prepended header ap-
	      pears before the second etc. prepended header.

	      Note: this action	must execute before the	message	content	is re-
	      ceived;	 it    cannot	 execute    in	  the	 context    of
	      smtpd_end_of_data_restrictions.

	      This feature is available	in Postfix 2.1 and later.

       REDIRECT	user@domain
	      After  the  message is queued, send the message to the specified
	      address instead of the intended recipient(s).

	      Note: this action	overrides the FILTER action, and currently af-
	      fects all	recipients of the message.

	      This feature is available	in Postfix 2.1 and later.

       WARN optional text...
	      Log  a  warning with the optional	text, together with client in-
	      formation	and if available, with	helo,  sender,	recipient  and
	      protocol information.

	      This feature is available	in Postfix 2.1 and later.

ENHANCED STATUS	CODES
       Postfix	version	2.3 and	later support enhanced status codes as defined
       in RFC 3463.  When an enhanced status code is specified	in  an	access
       table, it is subject to modification. The following transformations are
       needed when the same access table is used for client, helo, sender,  or
       recipient  access restrictions; they happen regardless of whether Post-
       fix replies to a	MAIL FROM, RCPT	TO or other SMTP command.

       o      When a sender address matches a REJECT action, the Postfix  SMTP
	      server will transform a recipient	DSN status (e.g., 4.1.1-4.1.6)
	      into the corresponding sender DSN	status,	and vice versa.

       o      When non-address information matches a REJECT  action  (such  as
	      the  HELO	 command argument or the client	hostname/address), the
	      Postfix SMTP server will transform a  sender  or	recipient  DSN
	      status into a generic non-address	DSN status (e.g., 4.0.0).

REGULAR	EXPRESSION TABLES
       This  section  describes	how the	table lookups change when the table is
       given in	the form of regular expressions. For a description of  regular
       expression lookup table syntax, see regexp_table(5) or pcre_table(5).

       Each  pattern  is  a  regular  expression that is applied to the	entire
       string being looked up. Depending on the	application, that string is an
       entire  client hostname,	an entire client IP address, or	an entire mail
       address.	Thus, no parent	domain	or  parent  network  search  is	 done,
       user@domain  mail  addresses are	not broken up into their user@ and do-
       main constituent	parts, nor is user+foo broken up into user and foo.

       Patterns	are applied in the order as specified in the  table,  until  a
       pattern is found	that matches the search	string.

       Actions	are the	same as	with indexed file lookups, with	the additional
       feature that parenthesized substrings from the pattern can be  interpo-
       lated as	$1, $2 and so on.

TCP-BASED TABLES
       This  section  describes	 how the table lookups change when lookups are
       directed	 to  a	TCP-based  server.  For	 a  description	 of  the   TCP
       client/server  lookup  protocol,	see tcp_table(5).  This	feature	is not
       available up to and including Postfix version 2.4.

       Each lookup operation uses the entire query string once.	 Depending  on
       the  application,  that	string is an entire client hostname, an	entire
       client IP address, or an	entire mail address.  Thus, no	parent	domain
       or  parent  network  search is done, user@domain	mail addresses are not
       broken up into  their  user@  and  domain  constituent  parts,  nor  is
       user+foo	broken up into user and	foo.

       Actions are the same as with indexed file lookups.

EXAMPLE
       The  following example uses an indexed file, so that the	order of table
       entries does not	matter.	The example permits access by  the  client  at
       address 1.2.3.4 but rejects all other clients in	1.2.3.0/24. Instead of
       hash lookup tables, some	systems	use dbm.  Use  the  command  "postconf
       -m" to find out what lookup tables Postfix supports on your system.

       /usr/local/etc/postfix/main.cf:
	   smtpd_client_restrictions =
	       check_client_access hash:$config_directory/access

       /usr/local/etc/postfix/access:
	   1.2.3   REJECT
	   1.2.3.4 OK

       Execute the command "postmap /usr/local/etc/postfix/access" after edit-
       ing the file.

BUGS
       The table format	does not understand quoting conventions.

SEE ALSO
       postmap(1), Postfix lookup table	manager
       smtpd(8), SMTP server
       postconf(5), configuration parameters
       transport(5), transport:nexthop syntax

README FILES
       Use "postconf readme_directory" or "postconf html_directory" to	locate
       this information.
       SMTPD_ACCESS_README, built-in SMTP server access	control
       DATABASE_README,	Postfix	lookup table overview

LICENSE
       The Secure Mailer license must be distributed with this software.

AUTHOR(S)
       Wietse Venema
       IBM T.J.	Watson Research
       P.O. Box	704
       Yorktown	Heights, NY 10598, USA

								     ACCESS(5)

NAME | SYNOPSIS | DESCRIPTION | CASE FOLDING | TABLE FORMAT | EMAIL ADDRESS PATTERNS | EMAIL ADDRESS EXTENSION | HOST NAME/ADDRESS PATTERNS | ACCEPT ACTIONS | REJECT ACTIONS | OTHER ACTIONS | ENHANCED STATUS CODES | REGULAR EXPRESSION TABLES | TCP-BASED TABLES | EXAMPLE | BUGS | SEE ALSO | README FILES | LICENSE | AUTHOR(S)

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