#++
# NAME
# regexp_table 5
# SUMMARY
# format of Postfix regular expression tables
# SYNOPSIS
# \fBregexp:/etc/postfix/\fIfilename\fR
#
# \fBpostmap -q "\fIstring\fB" regexp:/etc/postfix/\fIfilename\fR
#
# \fBpostmap -q - regexp:/etc/postfix/\fIfilename\fR <\fIinputfile\fR
# DESCRIPTION
# The Postfix mail system uses optional tables for address
# rewriting or mail routing. These tables are usually in
# \fBdbm\fR or \fBdb\fR format. Alternatively, lookup tables
# can be specified in POSIX regular expression form.
#
# To find out what types of lookup tables your Postfix system
# supports use the \fBpostconf -m\fR command.
#
# To test lookup tables, use the \fBpostmap\fR command as
# described in the SYNOPSIS above.
#
# The general form of a Postfix regular expression table is:
# .IP "\fB/\fIpattern\fB/\fIflags result\fR"
# .IP "\fB!/\fIpattern\fB/\fIflags result\fR"
# When \fIpattern\fR matches (does not match) a search string,
# use the corresponding \fIresult\fR value.
# .IP "blank lines and comments"
# Empty lines and whitespace-only lines are ignored, as
# are lines whose first non-whitespace character is a `#'.
# .IP "multi-line text"
# A logical line starts with non-whitespace text. A line that
# starts with whitespace continues a logical line.
# .IP "\fBif /\fIpattern\fB/\fIflags\fR"
# .IP "\fBif !/\fIpattern\fB/\fIflags\fR"
# .IP "\fBendif\fR"
# Examine the lines between \fBif\fR..\fBendif\fR only if
# \fIpattern\fR matches (does not match). The \fBif\fR..\fBendif\fR
# can nest.
# Do not prepend whitespace to patterns inside \fBif\fR..\fBendif\fR.
# .PP
# Each pattern is a regular expression enclosed by a pair of delimiters.
# The regular expression syntax is described in \fIre_format\fR(7).
# The expression delimiter can be any character, except whitespace
# or characters that have special meaning (traditionally the forward
# slash is used). The regular expression can contain whitespace.
#
# By default, matching is case-insensitive, although following
# the second slash with an `i' flag will reverse this. Other flags
# are `x' (disable extended expression syntax), and `m' (enable
# multi-line mode, that is, treat newline characters as special).
#
# 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
# \fIuser@domain\fR mail addresses are not broken up into their
# \fIuser\fR and \fIdomain\fR constituent parts, nor is \fIuser+foo\fR
# broken up into \fIuser\fR and \fIfoo\fR.
#
# Patterns are applied in the order as specified in the table, until a
# pattern is found that matches the search string.
#
# Substitution of substrings from the matched expression into the result
# string is possible using $1, $2, etc.. The macros in the result string
# may need to be written as ${n} or $(n) if they aren't followed
# by whitespace.
# EXAMPLE SMTPD ACCESS MAP
# # Disallow sender-specified routing. This is a must if you relay mail
# # for other domains.
# /[%!@].*[%!@]/ 550 Sender-specified routing rejected
#
# # Postmaster is OK, that way they can talk to us about how to fix
# # their problem.
# /^postmaster@/ OK
#
# # Protect your outgoing majordomo exploders
# if !/^owner-/
# /^(.*)-outgoing@(.*)$/ 550 Use ${1}@${2} instead
# endif
# EXAMPLE HEADER FILTER MAP
# # These were once common in junk mail.
# /^Subject: make money fast/ REJECT
# /^To: friend@public\\.com/ REJECT
# EXAMPLE BODY FILTER MAP
# # First skip over base 64 encoded text to save CPU cycles.
# ~^[[:alnum:]+/]{60,}$~ OK
#
# # Put your own body patterns here.
# SEE ALSO
# pcre_table(5) format of PCRE tables
# AUTHOR(S)
# The regexp table lookup code was originally written by:
# LaMont Jones
# lamont@hp.com
#
# That code was based on the PCRE dictionary contributed 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
#--