Postfix and REGEXP - Regular Expression tables

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Postfix Blacklist steps and examples...BlacklistSteps

Postfix REGEXP manual with examples....REGEXP



      regexp_table - format of Postfix regular expression tables


      postmap -q "string" regexp:/etc/postfix/filename
      postmap -q - regexp:/etc/postfix/filename <inputfile


      The Postfix mail system uses optional tables  for  address
      rewriting,  mail  routing, or access control. These tables
      are usually in dbm or db format.
      Alternatively, lookup tables can  be  specified  in  POSIX
      regular  expression form. In this case, each input is com-
      pared against a list of patterns. When a match  is  found,
      the  corresponding  result  is  returned and the search is
      To find out what types of lookup tables your Postfix  sys-
      tem supports use the "postconf -m" command.
      To  test  lookup  tables,  use the "postmap -q" command as
      described in the SYNOPSIS above.


      With Postfix version 2.2 and earlier specify "postmap -fq"
      to  query  a  table that contains case sensitive patterns.
      Patterns are case insensitive by default.


      The general form of a Postfix regular expression table is:
      /pattern/flags result
             When pattern matches the input string, use the cor-
             responding result value.
      !/pattern/flags result
             When pattern does not match the input  string,  use
             the corresponding result value.
      if /pattern/flags
      endif  Match the input string against the patterns between
             if and endif, if and only if that same input string
             also matches pattern. The if..endif can nest.
             Note:  do not prepend whitespace to patterns inside
             This feature is available in Postfix 2.1 and later.
      if !/pattern/flags
      endif  Match the input string against the patterns between
             if and endif, if and only if that same input string
             does not match pattern. The if..endif can nest.
             Note:  do not prepend whitespace to patterns inside
             This feature is available in Postfix 2.1 and later.
      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  logi-
             cal line.
      Each  pattern  is a POSIX regular expression enclosed by a
      pair of delimiters. The regular expression syntax is docu-
      mented  in  re_format(7)  with  4.4BSD,  in  regex(5) with
      Solaris, and in regex(7) with Linux. Other systems may use
      other document names.
      The  expression  delimiter  can  be  any character, except
      whitespace or characters that have special meaning (tradi-
      tionally  the  forward slash is used). The regular expres-
      sion can contain whitespace.
      By default, matching is case-insensitive, and newlines are
      not  treated  as  special characters. The behavior is con-
      trolled by flags, which are toggled by  appending  one  or
      more of the following characters after the pattern:
      i (default: on)
             Toggles  the  case  sensitivity  flag.  By default,
             matching is case insensitive.
      m (default: off)
             Toggle the multi-line mode flag. When this flag  is
             on,  the  ^  and $ metacharacters match immediately
             after and immediately before a  newline  character,
             respectively,  in addition to matching at the start
             and end of the input string.
      x (default: on)
             Toggles the extended  expression  syntax  flag.  By
             default,  support for extended expression syntax is


      Patterns are applied in the order as specified in the  ta-
      ble,  until  a  pattern  is  found  that matches the input
      Each pattern  is  applied  to  the  entire  input  string.
      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, and 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.


      Substitution of substrings  from  the  matched  expression
      into  the  result  string  is possible using $1, $2, etc.;
      specify $$ to produce a $ character as output.  The macros
      in  the  result  string  may need to be written as ${n} or
      $(n) if they aren't followed by whitespace.
      Note: since negated patterns (those preceded by !)  return
      a result when the expression does not match, substitutions
      are not available for negated patterns.


      # Disallow sender-specified routing. This is a must if you relay mail
      # for other domains.
      /[%!@].*[%!@]/       550 Sender-specified routing rejected
      # Postmaster is OK, that way they can talk to us about how to fix
      # their problem.
      /^postmaster@/       OK
      # Protect your outgoing majordomo exploders
      if !/^owner-/
      /^(.*)-outgoing@(.*)$/   550 Use ${1}@${2} instead


      # These were once common in junk mail.
      /^Subject: make money fast/     REJECT
      /^To: friend@public\.com/       REJECT


      # First skip over base 64 encoded text to save CPU cycles.
      ~^[[:alnum:]+/]{60,}$~          OK
      # Put your own body patterns here.


      postmap(1), Postfix lookup table manager
      pcre_table(5), format of PCRE tables
      cidr_table(5), format of CIDR tables


      DATABASE_README, Postfix lookup table overview


      The regexp table lookup code was originally written by:
      LaMont Jones
      That code was based on the PCRE dictionary contributed by:
      Andrew McNamara Pty. Ltd.
      Level 3, 213 Miller St
      North Sydney, NSW, Australia
      Adopted and adapted by:
      Wietse Venema
      IBM T.J. Watson Research
      P.O. Box 704
      Yorktown Heights, NY 10598, USA
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