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8REGEXP_TABLE(5)                                                REGEXP_TABLE(5)
9
10<b>NAME</b>
11       regexp_table - format of Postfix regular expression tables
12
13<b>SYNOPSIS</b>
14       <b>postmap -q "</b><i>string</i><b>" <a href="regexp_table.5.html">regexp</a>:/etc/postfix/</b><i>filename</i>
15
16       <b>postmap -q - <a href="regexp_table.5.html">regexp</a>:/etc/postfix/</b><i>filename</i> &lt;<i>inputfile</i>
17
18<b>DESCRIPTION</b>
19       The  Postfix  mail  system  uses optional tables for address rewriting,
20       mail routing, or access control. These tables are usually in <b>dbm</b> or  <b>db</b>
21       format.
22
23       Alternatively,  lookup tables can be specified in POSIX regular expres-
24       sion form. In this case, each input is compared against a list of  pat-
25       terns.  When a match is found, the corresponding result is returned and
26       the search is terminated.
27
28       To find out what types of lookup tables your  Postfix  system  supports
29       use the "<b>postconf -m</b>" command.
30
31       To test lookup tables, use the "<b>postmap -q</b>" command as described in the
32       SYNOPSIS above. Use "<b>postmap -hmq -</b> &lt;<i>file</i>"  for  <a href="header_checks.5.html">header_checks(5)</a>  pat-
33       terns,  and  "<b>postmap -bmq -</b> &lt;<i>file</i>" for <a href="header_checks.5.html">body_checks(5)</a> (Postfix 2.6 and
34       later).
35
36<b>COMPATIBILITY</b>
37       With Postfix version 2.2 and earlier specify "<b>postmap -fq</b>" to  query  a
38       table that contains case sensitive patterns. Patterns are case insensi-
39       tive by default.
40
41<b>TABLE FORMAT</b>
42       The general form of a Postfix regular expression table is:
43
44       <b>/</b><i>pattern</i><b>/</b><i>flags result</i>
45              When <i>pattern</i> matches the input  string,  use  the  corresponding
46              <i>result</i> value.
47
48       <b>!/</b><i>pattern</i><b>/</b><i>flags result</i>
49              When  <i>pattern</i>  does  <b>not</b>  match the input string, use the corre-
50              sponding <i>result</i> value.
51
52       <b>if /</b><i>pattern</i><b>/</b><i>flags</i>
53
54       <b>endif</b>  If the input string matches /<i>pattern</i>/,  then  match  that  input
55              string against the patterns between <b>if</b> and <b>endif</b>.  The <b>if</b>..<b>endif</b>
56              can nest.
57
58              Note: do not prepend whitespace to patterns inside <b>if</b>..<b>endif</b>.
59
60              This feature is available in Postfix 2.1 and later.
61
62       <b>if !/</b><i>pattern</i><b>/</b><i>flags</i>
63
64       <b>endif</b>  If the input string does not match /<i>pattern</i>/,  then  match  that
65              input  string  against  the  patterns  between <b>if</b> and <b>endif</b>. The
66              <b>if</b>..<b>endif</b> can nest.
67
68              Note: do not prepend whitespace to patterns inside <b>if</b>..<b>endif</b>.
69
70              This feature is available in Postfix 2.1 and later.
71
72       blank lines and comments
73              Empty lines and whitespace-only lines are ignored, as are  lines
74              whose first non-whitespace character is a `#'.
75
76       multi-line text
77              A  logical  line  starts  with  non-whitespace text. A line that
78              starts with whitespace continues a logical line.
79
80       Each pattern is a POSIX regular expression enclosed by a pair of delim-
81       iters. The regular expression syntax is documented in <b>re_format</b>(7) with
82       4.4BSD, in <b>regex</b>(5) with Solaris, and in  <b>regex</b>(7)  with  Linux.  Other
83       systems may use other document names.
84
85       The  expression  delimiter  can  be  any  non-alphanumerical character,
86       except whitespace or characters that have special  meaning  (tradition-
87       ally  the  forward  slash  is used). The regular expression can contain
88       whitespace.
89
90       By default, matching is case-insensitive, and newlines are not  treated
91       as  special  characters. The behavior is controlled by flags, which are
92       toggled by appending one or more of the following characters after  the
93       pattern:
94
95       <b>i</b> (default: on)
96              Toggles  the case sensitivity flag. By default, matching is case
97              insensitive.
98
99       <b>m</b> (default: off)
100              Toggle the multi-line mode flag. When this flag is on, the <b>^</b> and
101              <b>$</b>  metacharacters match immediately after and immediately before
102              a newline character, respectively, in addition  to  matching  at
103              the start and end of the input string.
104
105       <b>x</b> (default: on)
106              Toggles the extended expression syntax flag. By default, support
107              for extended expression syntax is enabled.
108
109<b>TABLE SEARCH ORDER</b>
110       Patterns are applied in the order as specified in the  table,  until  a
111       pattern is found that matches the input string.
112
113       Each  pattern  is applied to the entire input string.  Depending on the
114       application, that string is an entire client hostname, an entire client
115       IP  address, or an entire mail address.  Thus, no parent domain or par-
116       ent network search is done, and <i>user@domain</i> mail addresses are not bro-
117       ken  up  into  their <i>user</i> and <i>domain</i> constituent parts, nor is <i>user+foo</i>
118       broken up into <i>user</i> and <i>foo</i>.
119
120<b>TEXT SUBSTITUTION</b>
121       Substitution of substrings (text that  matches  patterns  inside  "()")
122       from  the  matched  expression into the result string is requested with
123       $1, $2, etc.; specify $$ to produce  a  $  character  as  output.   The
124       macros  in  the result string may need to be written as ${n} or $(n) if
125       they aren't followed by whitespace.
126
127       Note: since negated patterns (those preceded by <b>!</b>) return a result when
128       the  expression  does  not  match,  substitutions are not available for
129       negated patterns.
130
131<b>INLINE SPECIFICATION</b>
132       The contents of a table may be specified in the table name (Postfix 3.7
133       and later).  The basic syntax is:
134
135       <a href="postconf.5.html">main.cf</a>:
136           <i>parameter</i> <b>= .. <a href="regexp_table.5.html">regexp</a>:{ {</b> <i>rule-1</i> <b>}, {</b> <i>rule-2</i> <b>} .. } ..</b>
137
138       <a href="master.5.html">master.cf</a>:
139           <b>.. -o {</b> <i>parameter</i> <b>= .. <a href="regexp_table.5.html">regexp</a>:{ {</b> <i>rule-1</i> <b>}, {</b> <i>rule-2</i> <b>} .. } .. } ..</b>
140
141       Postfix  ignores  whitespace  after '{' and before '}', and writes each
142       <i>rule</i> as one text line to an in-memory file:
143
144       in-memory file:
145           rule-1
146           rule-2
147           ..
148
149       Postfix parses the result as if it is a file in /etc/postfix.
150
151       Note: if a rule contains <b>$</b>, specify <b>$$</b> to keep Postfix from  trying  to
152       do <i>$name</i> expansion as it evaluates a parameter value.
153
154<b>EXAMPLE SMTPD ACCESS MAP</b>
155       # Disallow sender-specified routing. This is a must if you relay mail
156       # for other domains.
157       /[%!@].*[%!@]/       550 Sender-specified routing rejected
158
159       # Postmaster is OK, that way they can talk to us about how to fix
160       # their problem.
161       /^postmaster@/       OK
162
163       # Protect your outgoing majordomo exploders
164       if !/^owner-/
165       /^(.*)-outgoing@(.*)$/  550 Use ${1}@${2} instead
166       endif
167
168<b>EXAMPLE HEADER FILTER MAP</b>
169       # These were once common in junk mail.
170       /^Subject: make money fast/     REJECT
171       /^To: friend@public\.com/       REJECT
172
173<b>EXAMPLE BODY FILTER MAP</b>
174       # First skip over base 64 encoded text to save CPU cycles.
175       ~^[[:alnum:]+/]{60,}$~          OK
176
177       # Put your own body patterns here.
178
179<b>SEE ALSO</b>
180       <a href="postmap.1.html">postmap(1)</a>, Postfix lookup table manager
181       <a href="pcre_table.5.html">pcre_table(5)</a>, format of PCRE tables
182       <a href="cidr_table.5.html">cidr_table(5)</a>, format of CIDR tables
183
184<b>README FILES</b>
185       <a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
186
187<b>AUTHOR(S)</b>
188       The regexp table lookup code was originally written by:
189       LaMont Jones
190       lamont@hp.com
191
192       That code was based on the PCRE dictionary contributed by:
193       Andrew McNamara
194       andrewm@connect.com.au
195       connect.com.au Pty. Ltd.
196       Level 3, 213 Miller St
197       North Sydney, NSW, Australia
198
199       Adopted and adapted by:
200       Wietse Venema
201       IBM T.J. Watson Research
202       P.O. Box 704
203       Yorktown Heights, NY 10598, USA
204
205       Wietse Venema
206       Google, Inc.
207       111 8th Avenue
208       New York, NY 10011, USA
209
210                                                               REGEXP_TABLE(5)
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