1PCRE_TABLE(5) File Formats Manual PCRE_TABLE(5)
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6 pcre_table - format of Postfix PCRE tables
7
9 postmap -q "string" pcre:/etc/postfix/filename
10 postmap -q - pcre:/etc/postfix/filename <inputfile
12 postmap -hmq - pcre:/etc/postfix/filename <inputfile
14 postmap -bmq - pcre:/etc/postfix/filename <inputfile
16
18 The Postfix mail system uses optional tables for address rewriting,
19 mail routing, or access control. These tables are usually in dbm or db
20 format.
21 Alternatively, lookup tables can be specified in Perl Compatible Regu‐
23 lar Expression form. In this case, each input is compared against a
24 list of patterns. When a match is found, the corresponding result is
25 returned and the search is terminated.
26 To find out what types of lookup tables your Postfix system supports
28 use the "postconf -m" command.
29 To test lookup tables, use the "postmap -q" command as described in the
31 SYNOPSIS above. Use "postmap -hmq - <file" for header_checks(5) pat‐
32 terns, and "postmap -bmq - <file" for body_checks(5) (Postfix 2.6 and
33 later).
34
36 With Postfix version 2.2 and earlier specify "postmap -fq" to query a
37 table that contains case sensitive patterns. Patterns are case insensi‐
38 tive by default.
39
41 The general form of a PCRE table is:
42 /pattern/flags result
44 When pattern matches the input string, use the corresponding
45 result value.
46 !/pattern/flags result
48 When pattern does not match the input string, use the corre‐
49 sponding result value.
50 if /pattern/flags
52 endif If the input string matches /pattern/, then match that input
54 string against the patterns between if and endif. The if..endif
55 can nest.
56 Note: do not prepend whitespace to patterns inside if..endif.
58 This feature is available in Postfix 2.1 and later.
60 if !/pattern/flags
62 endif If the input string does not match /pattern/, then match that
64 input string against the patterns between if and endif. The
65 if..endif can nest.
66 Note: do not prepend whitespace to patterns inside if..endif.
68 This feature is available in Postfix 2.1 and later.
70 blank lines and comments
72 Empty lines and whitespace-only lines are ignored, as are lines
73 whose first non-whitespace character is a `#'.
74 multi-line text
76 A logical line starts with non-whitespace text. A line that
77 starts with whitespace continues a logical line.
78 Each pattern is a perl-like regular expression. The expression delim‐
80 iter can be any non-alphanumerical character, except whitespace or
81 characters that have special meaning (traditionally the forward slash
82 is used). The regular expression can contain whitespace.
83 By default, matching is case-insensitive, and newlines are not treated
85 as special characters. The behavior is controlled by flags, which are
86 toggled by appending one or more of the following characters after the
87 pattern:
88 i (default: on)
90 Toggles the case sensitivity flag. By default, matching is case
91 insensitive.
92 m (default: off)
94 Toggles the PCRE_MULTILINE flag. When this flag is on, the ^ and
95 $ metacharacters match immediately after and immediately before
96 a newline character, respectively, in addition to matching at
97 the start and end of the subject string.
98 s (default: on)
100 Toggles the PCRE_DOTALL flag. When this flag is on, the .
101 metacharacter matches the newline character. With Postfix ver‐
102 sions prior to 2.0, the flag is off by default, which is incon‐
103 venient for multi-line message header matching.
104 x (default: off)
106 Toggles the pcre extended flag. When this flag is on, whitespace
107 characters in the pattern (other than in a character class) are
108 ignored. To include a whitespace character as part of the pat‐
109 tern, escape it with backslash.
110 Note: do not use #comment after patterns.
112 A (default: off)
114 Toggles the PCRE_ANCHORED flag. When this flag is on, the pat‐
115 tern is forced to be "anchored", that is, it is constrained to
116 match only at the start of the string which is being searched
117 (the "subject string"). This effect can also be achieved by
118 appropriate constructs in the pattern itself.
119 E (default: off)
121 Toggles the PCRE_DOLLAR_ENDONLY flag. When this flag is on, a $
122 metacharacter in the pattern matches only at the end of the sub‐
123 ject string. Without this flag, a dollar also matches immedi‐
124 ately before the final character if it is a newline character
125 (but not before any other newline characters). This flag is
126 ignored if PCRE_MULTILINE flag is set.
127 U (default: off)
129 Toggles the ungreedy matching flag. When this flag is on, the
130 pattern matching engine inverts the "greediness" of the quanti‐
131 fiers so that they are not greedy by default, but become greedy
132 if followed by "?". This flag can also set by a (?U) modifier
133 within the pattern.
134 X (default: off)
136 Toggles the PCRE_EXTRA flag. When this flag is on, any back‐
137 slash in a pattern that is followed by a letter that has no spe‐
138 cial meaning causes an error, thus reserving these combinations
139 for future expansion.
140
142 Patterns are applied in the order as specified in the table, until a
143 pattern is found that matches the input string.
144 Each pattern is applied to the entire input string. Depending on the
146 application, that string is an entire client hostname, an entire client
147 IP address, or an entire mail address. Thus, no parent domain or par‐
148 ent network search is done, and user@domain mail addresses are not bro‐
149 ken up into their user and domain constituent parts, nor is user+foo
150 broken up into user and foo.
151
153 Substitution of substrings (text that matches patterns inside "()")
154 from the matched expression into the result string is requested with
155 $1, $2, etc.; specify $$ to produce a $ character as output. The
156 macros in the result string may need to be written as ${n} or $(n) if
157 they aren't followed by whitespace.
158 Note: since negated patterns (those preceded by !) return a result when
160 the expression does not match, substitutions are not available for
161 negated patterns.
162
164 # Protect your outgoing majordomo exploders
165 /^(?!owner-)(.*)-outgoing@(.*)/ 550 Use ${1}@${2} instead
166 # Bounce friend@whatever, except when whatever is our domain (you would
168 # be better just bouncing all friend@ mail - this is just an example).
169 /^(friend@(?!my\.domain$).*)$/ 550 Stick this in your pipe $1
170 # A multi-line entry. The text is sent as one line.
172 #
173 /^noddy@my\.domain$/
174 550 This user is a funny one. You really don't want to send mail to
175 them as it only makes their head spin.
176
178 /^Subject: make money fast/ REJECT
179 /^To: friend@public\.com/ REJECT
180
182 # First skip over base 64 encoded text to save CPU cycles.
183 # Requires PCRE version 3.
184 ~^[[:alnum:]+/]{60,}$~ OK
185 # Put your own body patterns here.
187
189 postmap(1), Postfix lookup table manager
190 postconf(5), configuration parameters
191 regexp_table(5), format of POSIX regular expression tables
192
194 Use "postconf readme_directory" or "postconf html_directory" to locate
195 this information.
196 DATABASE_README, Postfix lookup table overview
197
199 The PCRE table lookup code was originally written by:
200 Andrew McNamara
201 andrewm@connect.com.au
202 connect.com.au Pty. Ltd.
203 Level 3, 213 Miller St
204 North Sydney, NSW, Australia
205 Adopted and adapted by:
207 Wietse Venema
208 IBM T.J. Watson Research
209 P.O. Box 704
210 Yorktown Heights, NY 10598, USA
211 Wietse Venema
213 Google, Inc.
214 111 8th Avenue
215 New York, NY 10011, USA
216 PCRE_TABLE(5)