Provided by: postfix_2.2.10-1_i386 bug

NAME

       access - Postfix access table format

SYNOPSIS

       postmap /etc/postfix/access

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

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

DESCRIPTION

       The  optional  access(5)  table  directs  the  Postfix  SMTP  server to
       selectively reject or accept mail. Access can be allowed or denied  for
       specific  host  names,  domain  names, networks, host addresses or mail
       addresses.

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

       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  /etc/postfix/access"  in  order  to  rebuild  the
       indexed file after changing the access 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  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 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_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 order
              to match subdomains.

       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
       examined 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_domain_matches_subdomains      configuration     setting.
              Otherwise, specify .domain.tld (note the initial dot)  in  order
              to match subdomains.

       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 information in the access map should be in 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/netmask 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 information in the access map should be in 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/netmask 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
              generated 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
              specified,  otherwise  reply  with  a  generic  error   response
              message.

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

              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 "450 optional
              text... when the optional text  is  specified,  otherwise  reply
              with a generic error response message.

              This feature is available in Postfix 2.1 and later.

OTHER ACTIONS

       restriction...
              Apply    the   named   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 specified, otherwise log a generic message.

              Note: this  action  currently  affects  all  recipients  of  the
              message.

              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:destination
              syntax  is  described  in  the  transport(5)  manual page.  More
              information about external content filters  is  in  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 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.

              Note: this  action  currently  affects  all  recipients  of  the
              message.

              This feature is available in 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.

              Note:  this  action  must  be used before the message content is
              received; it cannot be used in 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
              affects 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
              information  and  if available, with helo, sender, recipient and
              protocol information.

              This feature is available in Postfix 2.1 and later.

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
       domain  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
       interpolated 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 2.2.

       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.

       /etc/postfix/main.cf:
           smtpd_client_restrictions =
               check_client_access hash:/etc/postfix/access

       /etc/postfix/access:
           1.2.3   REJECT
           1.2.3.4 OK

       Execute the command "postmap /etc/postfix/access" 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(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)