    PCRE_TABLE(5)                                       PCRE_TABLE(5)

    NAME
           pcre_table - format of Postfix PCRE tables

    SYNOPSIS
           pcre:/etc/postfix/filename

    DESCRIPTION
           The  Postfix  mail system uses optional tables for address
           rewriting or mail routing. These tables are usually in dbm
           or  db  format. Alternatively, lookup tables can be speci-
           fied in Perl Compatible Regular Expression form.

           To find out what types of lookup tables your Postfix  sys-
           tem supports use the postconf -m command.

           The general form of a PCRE table is:

           blanks and comments
                  Blank  lines  are  ignored,  as are lines beginning
                  with `#'.

           leading whitespace
                  Lines that begin with whitespace continue the  pre-
                  vious line.

           pattern result
                  When  pattern matches a search string, use the cor-
                  responding result. A line that  starts  with  white
                  space continues the preceding line.

           Each  pattern  is  a  perl-like  regular  expression.  The
           expression delimiter can be any character, except  whites-
           pace  or  characters that have special meaning (tradition-
           ally the forward slash is used).  The  regular  expression
           can contain whitespace.

           By default, matching is case-insensitive, although follow-
           ing the second slash with an `i' flag will  reverse  this.
           Other  flags  are supported, but the only other useful one
           is `U', which makes matching ungreedy (see PCRE documenta-
           tion and source for more info).

           Each  pattern  is applied to the entire lookup key 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.

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

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    PCRE_TABLE(5)                                       PCRE_TABLE(5)

           Substitution  of  substrings  from  the matched expression
           into the result string is possible using the  conventional
           perl  syntax  ($1,  $2,  etc.).   The macros in the result
           string may need to be written as  ${n}  or  $(n)  if  they
           aren't followed by whitespace.

    EXAMPLES
           # Protect your outgoing majordomo exploders
           /^(?!owner-)(.*)-outgoing@(my.domain)$/    550 Use ${1}@${2} instead

           # Bounce friend@whatever, except when whatever is our domain (you would
           # be better just bouncing all friend@ mail - this is just an example).
           /^friend@(?!my.domain).*$/         550 Stick this in your pipe $0

           # A multi-line entry. The text is sent as one line.
           #
           /^noddy@connect.com.au$/
            550 This user is a funny one. You really don't want to send mail to
            them as it only makes their head spin.

    SEE ALSO
           regexp_table(5) format of POSIX regular expression tables

    AUTHOR(S)
           The PCRE table lookup code was originally written by:
           Andrew McNamara
           andrewm@connect.com.au
           connect.com.au 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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