Provided by: postfix_2.8.5-2~build1_i386 bug

NAME

       access - Postfix SMTP server access table

SYNOPSIS

       postmap /etc/postfix/access

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

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

DESCRIPTION

       This   document   describes   access  control  on  remote  SMTP  client
       information: 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 /etc/postfix/access" to rebuild  an  indexed  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
       directed to TCP-based server. In those cases, the lookups are done in a
       slightly  different  way  as  described below under "REGULAR EXPRESSION
       TABLES" 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_domain_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_domain_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
       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.

       .domain.tld
              Matches  subdomains  of  domain.tld,  but  only  when the string
              smtpd_access_maps    is    not    listed    in    the    Postfix
              parent_domain_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
              network address information 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 access map lookup key must be in canonical form:  do
              not  specify  unnecessary  null  characters,  and do not enclose
              network address information 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  such  as
              pop-before-smtp.

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
                     concern.   The  "send 521 and disconnect" behavior is NOT
                     defined 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
              message.

              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_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.

OTHER ACTIONS

       restriction...
              Apply    the   named   UCE   restriction(s)   (permit,   reject,
              reject_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
              message.   To  discard only one recipient without discarding the
              entire 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
              master.cf; the syntax of the next-hop destination  is  described
              in  the  manual  page of the corresponding delivery agent.  More
              information about external content filters  is  in  the  Postfix
              FILTER_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
              setting, and affects all recipients of the message. In the  case
              that  multiple  FILTER  actions  fire,  only  the  last  one  is
              executed.

              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
              (Postfix 2.7 and later), or specify a transport:destination that
              delivers 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
              message.

              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
              appears before the second etc. prepended header.

              Note:  this  action  must  execute before the message content is
              received;   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
              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.

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
       Postfix 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
       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 2.4.

       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.

       /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)