PCRE_TABLE(5)                                                    PCRE_TABLE(5)

       pcre_table - format of Postfix PCRE tables

       postmap -q "string" pcre:/etc/postfix/filename

       postmap -q - pcre:/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 Perl Com-
       patible Regular Expression form. In this case, each  input
       is  compared  against  a list of patterns. When a match is
       found, the corresponding result is returned and the search
       is terminated.

       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 PCRE 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 the 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 the 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  perl-like  regular  expression.  The
       expression delimiter can be any character,  except  white-
       space  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, 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)
              Toggles  the PCRE_MULTILINE 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 subject string.

       s (default: on)
              Toggles the PCRE_DOTALL flag. When this flag is on,
              the .  metacharacter matches the newline character.
              With Postfix versions prior to 2.0, The flag is off
              by default, which is  inconvenient  for  multi-line
              message header matching.

       x (default: off)
              Toggles  the  pcre extended flag. When this flag is
              on, whitespace in the  pattern  (other  than  in  a
              character class) and characters between a # outside
              a character class and the  next  newline  character
              are  ignored.  An escaping backslash can be used to
              include a whitespace or # character as part of  the

       A (default: off)
              Toggles  the PCRE_ANCHORED flag.  When this flag is
              on, the pattern is forced to  be  "anchored",  that
              is, it is constrained to match only at the start of
              the string which is being  searched  (the  "subject
              string").  This  effect  can  also  be  achieved by
              appropriate constructs in the pattern itself.

       E (default: off)
              Toggles the  PCRE_DOLLAR_ENDONLY  flag.  When  this
              flag  is  on,  a  $  metacharacter  in  the pattern
              matches only at the  end  of  the  subject  string.
              Without  this  flag,  a dollar also matches immedi-
              ately before the final character if it is a newline
              character (but not before any other newline charac-
              ters). This flag is ignored if PCRE_MULTILINE  flag
              is set.

       U (default: off)
              Toggles the ungreedy matching flag.  When this flag
              is on, the  pattern  matching  engine  inverts  the
              "greediness"  of  the  quantifiers so that they are
              not greedy by default, but become  greedy  if  fol-
              lowed  by  "?".   This  flag can also set by a (?U)
              modifier within the pattern.

       X (default: off)
              Toggles the PCRE_EXTRA flag.  When this flag is on,
              any  backslash  in  a pattern that is followed by a
              letter that has no special meaning causes an error,
              thus reserving these combinations for future expan-

       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 the conventional
       perl syntax ($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.

       # Protect your outgoing majordomo exploders
       /^(?!owner-)(.*)-outgoing@(.*)/ 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 $1

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

       /^Subject: make money fast/     REJECT
       /^To: friend@public\.com/       REJECT

       # First skip over base 64 encoded text to save CPU cycles.
       # Requires PCRE version 3.
       ~^[[:alnum:]+/]{60,}$~          OK

       # Put your own body patterns here.

       postmap(1), Postfix lookup table manager
       postconf(5), configuration parameters
       regexp_table(5), format of POSIX regular expression tables

       DATABASE_README, Postfix lookup table overview

       The PCRE table lookup code was originally written by:
       Andrew McNamara
       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