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ACCESS(5)                                                            ACCESS(5)



NAME
       access(2,5) - Postfix access(2,5) table format

SYNOPSIS
       postmap /etc/postfix/access(2,5)

       postmap -q "string(3,n)" /etc/postfix/access(2,5)

       postmap -q - /etc/postfix/access(2,5) <inputfile

DESCRIPTION
       The  optional access(2,5)(5) table directs the Postfix SMTP server to selec-
       tively reject or accept(2,8) mail. Access can be allowed or denied for  spe-
       cific  host(1,5)  names,  domain  names,  networks,  host(1,5)  addresses or mail(1,8)
       addresses.

       For an example, see the EXAMPLE section at the end of this manual page.

       Normally,  the  access(2,5)(5) table is specified as a text file(1,n) that serves
       as input to the postmap(1) command.  The result, an indexed file(1,n) in(1,8) dbm
       or  db  format,  is used for fast searching by the mail(1,8) system. Execute
       the command "postmap  /etc/postfix/access(2,5)"  in(1,8)  order  to  rebuild  the
       indexed file(1,n) after changing the access(2,5) table.

       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
       directed to TCP-based server. In that case, the lookups are done  in(1,8)  a
       slightly  different  way  as  described below under "REGULAR EXPRESSION
       TABLES" and "TCP-BASED TABLES".

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

       pattern action
              When pattern matches a mail(1,8) address,  domain  or  host(1,5)  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(1,8)  the  order  as
       listed below:

       user@domain
              Matches the specified mail(1,8) 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(3,n) smtpd_access_maps  is  listed  in(1,8)  the  Postfix  par-
              ent_domain_matches_subdomains  configuration  setting (note that
              this is the default for some versions of  Postfix).   Otherwise,
              specify  .domain.tld  (note  the  initial dot) in(1,8) order to match
              subdomains.

       user@  Matches all mail(1,8) 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(1,8) the Postfix main.cf file.

EMAIL ADDRESS EXTENSION
       When a mail(1,8) 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
       examined in(1,8) the order as listed:

       domain.tld
              Matches domain.tld.

              The  pattern  domain.tld  also matches subdomains, but only when
              the string(3,n) smtpd_access_maps  is  listed  in(1,8)  the  Postfix  par-
              ent_domain_matches_subdomains configuration setting.  Otherwise,
              specify .domain.tld (note the initial dot)  in(1,8)  order  to  match
              subdomains.

       net.work.addr.ess

       net.work.addr

       net.work

       net    Matches  the  specified IPv4 host(1,5) address or subnetwork. An IPv4
              host(1,5) address is a sequence of four decimal octets  separated  by
              ".".

              Subnetworks  are  matched  by  repeatedly  truncating  the  last
              ".octet" from the remote IPv4 host(1,5) address string(3,n) until a  match
              is found in(1,8) the access(2,5) table, or until further truncation is not
              possible.

              NOTE 1: The information in(1,8) the access(2,5) map should be in(1,8) canonical
              form,  with  unnecessary  null  characters  eliminated.  Address
              information must not be enclosed 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(1,5) address or subnetwork. An IPv6
              host(1,5) 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(1,5) address  string(3,n)  until  a
              match  is found in(1,8) the access(2,5) table, or until further truncation
              is not possible.

              NOTE 1: the truncation and comparison are done with  the  string(3,n)
              representation  of  the IPv6 host(1,5) address. Thus, not all the ":"
              subnetworks will be tried.

              NOTE 2: The information in(1,8) the access(2,5) map should be in(1,8) canonical
              form,  with  unnecessary  null  characters  eliminated.  Address
              information must not be enclosed 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(1,8) 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.

REJECT ACTIONS
       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".

       REJECT optional text...
              Reject the address etc. that matches  the  pattern.  Reply  with
              $reject_code  optional  text... when the optional text is speci-
              fied, otherwise reply with a generic error(8,n) response message.

       DEFER_IF_REJECT optional text...
              Defer the request if(3,n) some later restriction would  result  in(1,8)  a
              REJECT  action.  Reply  with  "450  optional  text...  when  the
              optional text is specified, otherwise reply with a generic error(8,n)
              response message.

              This feature is available in(1,8) Postfix 2.1 and later.

       DEFER_IF_PERMIT optional text...
              Defer the request if(3,n) some later restriction would result in(1,8) a an
              explicit or implicit PERMIT action.  Reply  with  "450  optional
              text...  when  the  optional  text is specified, otherwise reply
              with a generic error(8,n) response message.

              This feature is available in(1,8) Postfix 2.1 and later.

OTHER ACTIONS
       restriction...
              Apply   the   named(5,8)   UCE   restriction(s)   (permit,    reject,
              reject_unauth_destination, and so on).

       DISCARD optional text...
              Claim successful delivery and silently discard the message.  Log
              the optional text if(3,n) specified, otherwise log a generic message.

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

              This feature is available in(1,8) 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(1,8) Postfix 2.0 and later.

       FILTER transport:destination
              After the message is queued, send(2,n) the entire message through the
              specified  external  content  filter.  The transport:destination
              syntax is described  in(1,8)  the  transport(5)  manual  page.   More
              information  about  external  content  filters is in(1,8) the Postfix
              FILTER_README file.

              Note: this action overrides the main.cf content_filter  setting,
              and currently affects all recipients of the message.

              This feature is available in(1,8) Postfix 2.0 and later.

       HOLD optional text...
              Place  the  message  on  the hold queue(1,3), where it will sit until
              someone either deletes it or releases it for delivery.  Log  the
              optional text if(3,n) 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(1,8) that was kept on hold
              for  a  significant  fraction  of   $maximal_queue_lifetime   or
              $bounce_queue_lifetime, or longer.

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

              This feature is available in(1,8) Postfix 2.0 and later.

       PREPEND headername: headervalue
              Prepend the specified message header to the message.  When  this
              action  is  used  multiple  times,  the  first  prepended header
              appears before the second etc. prepended header.

              Note: this action does not support multi-line message headers.

              This feature is available in(1,8) Postfix 2.1 and later.

       REDIRECT user@domain
              After the message is queued, send(2,n) the message to  the  specified
              address instead of the intended recipient(s).

              Note:  this  action  overrides  the FILTER action, and currently
              affects all recipients of the message.

              This feature is available in(1,8) Postfix 2.1 and later.

       WARN optional text...
              Log a warning with  the  optional  text,  together  with  client
              information  and  if(3,n) available, with helo, sender, recipient and
              protocol information.

              This feature is available in(1,8) Postfix 2.1 and later.

REGULAR EXPRESSION TABLES
       This section describes how the table lookups change when the  table  is
       given  in(1,8) 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(3,n) being looked up. Depending on the application, that string(3,n) is an
       entire client hostname, an entire client IP address, or an entire  mail(1,8)
       address.  Thus,  no  parent  domain  or  parent network search is done,
       user@domain mail(1,8) addresses are not  broken  up  into  their  user@  and
       domain  constituent parts, nor is user+foo broken up into user and foo.

       Patterns are applied in(1,8) the order as specified in(1,8) the  table,  until  a
       pattern is found that matches the search string.

       Actions  are the same as with indexed file(1,n) 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(1,3,5) 2.2.

       Each lookup operation uses the entire query string(3,n) once.  Depending  on
       the  application,  that  string(3,n) is an entire client hostname, an entire
       client IP address, or an entire mail(1,8) address.  Thus, no  parent  domain
       or  parent  network  search is done, user@domain mail(1,8) 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(1,n) lookups.

EXAMPLE
       The  following example uses an indexed file(1,n), so that the order of table
       entries does not matter. The example permits access(2,5) by  the  client  at
       address 1.2.3.4 but rejects all other clients in(1,8) 1.2.3.0/24. Instead of
       hash lookup tables, some systems use dbm.  Use  the  command  "postconf(1,5)
       -m" to find out what lookup tables Postfix supports on your system.

       /etc/postfix/main.cf:
           smtpd_client_restrictions =
               check_client_access hash:/etc/postfix/access(2,5)

       /etc/postfix/access:
           1.2.3   REJECT
           1.2.3.4 OK

       Execute the command "postmap /etc/postfix/access(2,5)" after
       editing the file.

BUGS
       The table format does not understand quoting conventions.

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

README FILES
       Use  "postconf(1,5) readme_directory" or "postconf(1,5) html_directory" to locate
       this information.
       SMTPD_ACCESS_README, built-in SMTP server access(2,5) 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)

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