#++
# NAME
# regexp_table 5
# SUMMARY
# format of Postfix regular expression tables
# SYNOPSIS
# \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, mail routing, or access control. These tables
# are usually in \fBdbm\fR or \fBdb\fR format.
#
# Alternatively, lookup tables can be specified in POSIX 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 system
# supports use the "\fBpostconf -m\fR" command.
#
# To test lookup tables, use the "\fBpostmap -q\fR" command
# as described in the SYNOPSIS above.
# COMPATIBILITY
# .ad
# .fi
# With Postfix version 2.2 and earlier specify "\fBpostmap
# -fq\fR" to query a table that contains case sensitive
# patterns. Patterns are case insensitive by default.
# TABLE FORMAT
# .ad
# .fi
# The general form of a Postfix regular expression table is:
# .IP "\fB/\fIpattern\fB/\fIflags result\fR"
# When \fIpattern\fR matches the input string,
# use the corresponding \fIresult\fR value.
# .IP "\fB!/\fIpattern\fB/\fIflags result\fR"
# When \fIpattern\fR does \fBnot\fR match the input string,
# use the corresponding \fIresult\fR value.
# .IP "\fBif /\fIpattern\fB/\fIflags\fR"
# .IP "\fBendif\fR"
# Match the input string against the patterns between \fBif\fR
# and \fBendif\fR, if and only if that same input string also
# matches \fIpattern\fR. The \fBif\fR..\fBendif\fR can nest.
# .sp
# Note: do not prepend whitespace to patterns inside
# \fBif\fR..\fBendif\fR.
# .sp
# This feature is available in Postfix 2.1 and later.
# .IP "\fBif !/\fIpattern\fB/\fIflags\fR"
# .IP "\fBendif\fR"
# Match the input string against the patterns between \fBif\fR
# and \fBendif\fR, if and only if that same input string does
# \fBnot\fR match \fIpattern\fR. The \fBif\fR..\fBendif\fR can nest.
# .sp
# Note: do not prepend whitespace to patterns inside
# \fBif\fR..\fBendif\fR.
# .sp
# This feature is available in Postfix 2.1 and later.
# .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.
# .PP
# Each pattern is a POSIX regular expression enclosed by a pair of
# delimiters. The regular expression syntax is documented in
# \fBre_format\fR(7) with 4.4BSD, in \fBregex\fR(5) with Solaris, and in
# \fBregex\fR(7) with Linux. Other systems may use other document names.
#
# The expression delimiter can be any non-alphanumerical
# 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, and newlines are not
# treated as special characters. The behavior is controlled by flags,
# which are toggled by appending one or more of the following
# characters after the pattern:
# .IP "\fBi\fR (default: on)"
# Toggles the case sensitivity flag. By default, matching is case
# insensitive.
# .IP "\fBm\fR (default: off)"
# Toggle the multi-line mode flag. When this flag is on, the \fB^\fR
# and \fB$\fR metacharacters match immediately after and immediately
# before a newline character, respectively, in addition to
# matching at the start and end of the input string.
# .IP "\fBx\fR (default: on)"
# Toggles the extended expression syntax flag. By default, support
# for extended expression syntax is enabled.
# TABLE SEARCH ORDER
# .ad
# .fi
# Patterns are applied in the order as specified in the table, until a
# pattern is found that matches the input string.
#
# 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
# \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.
# TEXT SUBSTITUTION
# .ad
# .fi
# 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 $(n) if they aren't followed
# by whitespace.
#
# Note: since negated patterns (those preceded by \fB!\fR) return a
# result when the expression does not match, substitutions are not
# available for negated patterns.
# EXAMPLE SMTPD ACCESS MAP
# # Disallow sender-specified routing. This is a must if you relay mail
# # for other domains.
# /[%!@].*[%!@]/ 550 Sender-specified routing rejected
#
# # Postmaster is OK, that way they can talk to us about how to fix
# # their problem.
# /^postmaster@/ OK
#
# # Protect your outgoing majordomo exploders
# if !/^owner-/
# /^(.*)-outgoing@(.*)$/ 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
# postmap(1), Postfix lookup table manager
# pcre_table(5), format of PCRE tables
# cidr_table(5), format of CIDR tables
# README FILES
# .ad
# .fi
# Use "\fBpostconf readme_directory\fR" or
# "\fBpostconf html_directory\fR" to locate this information.
# .na
# .nf
# DATABASE_README, Postfix lookup table overview
# 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
#--