    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 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, 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 sub-strings from the matched expression is
           possible using  the  conventional  perl  syntax  ($1,  $2,
           etc.). The macros in the replacement string may need to be
           written as ${n} or $(n) if they aren't followed by whites-
           pace.

    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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