NetBSD/gnu/dist/postfix/html/pcre_table.5.html

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PCRE_TABLE(5) PCRE_TABLE(5)
<b>NAME</b>
pcre_table - format of Postfix PCRE tables
<b>SYNOPSIS</b>
pcre:/etc/postfix/filename
<b>DESCRIPTION</b>
The Postfix mail system uses optional tables for address
rewriting or mail routing. These tables are usually in <b>dbm</b>
or <b>db</b> 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 <b>postconf</b> <b>-m</b> command.
The general form of a PCRE table is:
<i>pattern</i> <i>result</i>
When <i>pattern</i> matches a search string, use the cor-
responding <i>result</i>.
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 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 <i>user@domain</i> mail addresses are not
broken up into their <i>user</i> and <i>domain</i> constituent parts,
nor is <i>user+foo</i> broken up into <i>user</i> and <i>foo</i>.
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 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.
<b>EXAMPLE</b> <b>SMTPD</b> <b>ACCESS</b> <b>MAP</b>
# 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 $0
# A multi-line entry. The text is sent as one line.
#
/^noddy@my\.domain$/
550 This user is a funny one. You really don't want to send mail to
them as it only makes their head spin.
<b>EXAMPLE</b> <b>HEADER</b> <b>FILTER</b> <b>MAP</b>
/^Subject: make money fast/ REJECT
/^To: friend@public\.com/ REJECT
<b>SEE</b> <b>ALSO</b>
<a href="regexp_table.5.html">regexp_table(5)</a> format of POSIX regular expression tables
<b>AUTHOR(S)</b>
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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