postfix-master/pcre_table.5.html

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   7 PCRE_TABLE(5)                                                    PCRE_TABLE(5)
   8
   9 <b>NAME</b>
  10        pcre_table - format of Postfix PCRE tables
  11
  12 <b>SYNOPSIS</b>
  13        <b>postmap -q "</b><i>string</i><b>" <a href="pcre_table.5.html">pcre</a>:/etc/postfix/</b><i>filename</i>
  14
  15        <b>postmap -q - <a href="pcre_table.5.html">pcre</a>:/etc/postfix/</b><i>filename</i> &lt;<i>inputfile</i>
  16
  17 <b>DESCRIPTION</b>
  18        The  Postfix  mail system uses optional tables for address
  19        rewriting, mail routing, or access control.  These  tables
  20        are usually in <b>dbm</b> or <b>db</b> format.
  21
  22        Alternatively, lookup tables can be specified in Perl Com-
  23        patible Regular Expression form. In this case, each  input
  24        is  compared  against  a list of patterns. When a match is
  25        found, the corresponding result is returned and the search
  26        is terminated.
  27
  28        To  find out what types of lookup tables your Postfix sys-
  29        tem supports use the "<b>postconf -m</b>" command.
  30
  31        To test lookup tables, use the  "<b>postmap  -q</b>"  command  as
  32        described in the SYNOPSIS above.
  33
  34 <b>COMPATIBILITY</b>
  35        With Postfix version 2.2 and earlier specify "<b>postmap -fq</b>"
  36        to query a table that contains  case  sensitive  patterns.
  37        Patterns are case insensitive by default.
  38
  39 <b>TABLE FORMAT</b>
  40        The general form of a PCRE table is:
  41
  42        <b>/</b><i>pattern</i><b>/</b><i>flags result</i>
  43               When <i>pattern</i> matches the input string, use the cor-
  44               responding <i>result</i> value.
  45
  46        <b>!/</b><i>pattern</i><b>/</b><i>flags result</i>
  47               When <i>pattern</i> does <b>not</b> match the input  string,  use
  48               the corresponding <i>result</i> value.
  49
  50        <b>if /</b><i>pattern</i><b>/</b><i>flags</i>
  51
  52        <b>endif</b>  Match the input string against the patterns between
  53               <b>if</b> and <b>endif</b>, if and only if that same input string
  54               also matches <i>pattern</i>. The <b>if</b>..<b>endif</b> can nest.
  55
  56               Note:  do not prepend whitespace to patterns inside
  57               <b>if</b>..<b>endif</b>.
  58
  59               This feature is available in Postfix 2.1 and later.
  60
  61        <b>if !/</b><i>pattern</i><b>/</b><i>flags</i>
  62
  63        <b>endif</b>  Match the input string against the patterns between
  64               <b>if</b> and <b>endif</b>, if and only if that same input string
  65               does <b>not</b> match <i>pattern</i>. The <b>if</b>..<b>endif</b> can nest.
  66
  67               Note:  do not prepend whitespace to patterns inside
  68               <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,
  74               as are lines whose first  non-whitespace  character
  75               is a `#'.
  76
  77        multi-line text
  78               A  logical  line starts with non-whitespace text. A
  79               line that starts with whitespace continues a  logi-
  80               cal line.
  81
  82        Each  pattern  is  a  perl-like  regular  expression.  The
  83        expression delimiter can be any non-alphanumerical charac-
  84        ter,  except  whitespace  or  characters that have special
  85        meaning (traditionally the forward slash  is  used).   The
  86        regular expression can contain whitespace.
  87
  88        By default, matching is case-insensitive, and newlines are
  89        not treated as special characters. The  behavior  is  con-
  90        trolled  by  flags,  which are toggled by appending one or
  91        more of the following characters after the pattern:
  92
  93        <b>i</b> (default: on)
  94               Toggles the  case  sensitivity  flag.  By  default,
  95               matching is case insensitive.
  96
  97        <b>m</b> (default: off)
  98               Toggles  the PCRE_MULTILINE flag. When this flag is
  99               on, the <b>^</b> and <b>$</b>  metacharacters  match  immediately
 100               after  and  immediately before a newline character,
 101               respectively, in addition to matching at the  start
 102               and end of the subject string.
 103
 104        <b>s</b> (default: on)
 105               Toggles the PCRE_DOTALL flag. When this flag is on,
 106               the <b>.</b>  metacharacter matches the newline character.
 107               With Postfix versions prior to 2.0, the flag is off
 108               by default, which is  inconvenient  for  multi-line
 109               message header matching.
 110
 111        <b>x</b> (default: off)
 112               Toggles  the  pcre extended flag. When this flag is
 113               on, whitespace characters  in  the  pattern  (other
 114               than in a character class) are ignored.  To include
 115               a whitespace character  as  part  of  the  pattern,
 116               escape it with backslash.
 117
 118               Note: do not use <b>#</b><i>comment</i> after patterns.
 119
 120        <b>A</b> (default: off)
 121               Toggles  the PCRE_ANCHORED flag.  When this flag is
 122               on, the pattern is forced to  be  "anchored",  that
 123               is, it is constrained to match only at the start of
 124               the string which is being  searched  (the  "subject
 125               string").  This  effect  can  also  be  achieved by
 126               appropriate constructs in the pattern itself.
 127
 128        <b>E</b> (default: off)
 129               Toggles the  PCRE_DOLLAR_ENDONLY  flag.  When  this
 130               flag  is  on,  a  <b>$</b>  metacharacter  in  the pattern
 131               matches only at the  end  of  the  subject  string.
 132               Without  this  flag,  a dollar also matches immedi-
 133               ately before the final character if it is a newline
 134               character (but not before any other newline charac-
 135               ters). This flag is ignored if PCRE_MULTILINE  flag
 136               is set.
 137
 138        <b>U</b> (default: off)
 139               Toggles the ungreedy matching flag.  When this flag
 140               is on, the  pattern  matching  engine  inverts  the
 141               "greediness"  of  the  quantifiers so that they are
 142               not greedy by default, but become  greedy  if  fol-
 143               lowed  by  "?".   This  flag can also set by a (?U)
 144               modifier within the pattern.
 145
 146        <b>X</b> (default: off)
 147               Toggles the PCRE_EXTRA flag.  When this flag is on,
 148               any  backslash  in  a pattern that is followed by a
 149               letter that has no special meaning causes an error,
 150               thus reserving these combinations for future expan-
 151               sion.
 152
 153 <b>SEARCH ORDER</b>
 154        Patterns are applied in the order as specified in the  ta-
 155        ble,  until  a  pattern  is  found  that matches the input
 156        string.
 157
 158        Each pattern  is  applied  to  the  entire  input  string.
 159        Depending  on  the  application,  that string is an entire
 160        client hostname, an entire client IP address, or an entire
 161        mail  address.   Thus,  no parent domain or parent network
 162        search is done, and <i>user@domain</i>  mail  addresses  are  not
 163        broken  up  into  their <i>user</i> and <i>domain</i> constituent parts,
 164        nor is <i>user+foo</i> broken up into <i>user</i> and <i>foo</i>.
 165
 166 <b>TEXT SUBSTITUTION</b>
 167        Substitution of substrings  from  the  matched  expression
 168        into  the result string is possible using the conventional
 169        perl syntax ($1, $2, etc.); specify  $$  to  produce  a  $
 170        character  as output.  The macros in the result string may
 171        need to be written as ${n} or $(n) if they aren't followed
 172        by whitespace.
 173
 174        Note:  since negated patterns (those preceded by <b>!</b>) return
 175        a result when the expression does not match, substitutions
 176        are not available for negated patterns.
 177
 178 <b>EXAMPLE SMTPD ACCESS MAP</b>
 179        # Protect your outgoing majordomo exploders
 180        /^(?!owner-)(.*)-outgoing@(.*)/ 550 Use ${1}@${2} instead
 181
 182        # Bounce friend@whatever, except when whatever is our domain (you would
 183        # be better just bouncing all friend@ mail - this is just an example).
 184        /^(friend@(?!my\.domain$).*)$/  550 Stick this in your pipe $1
 185
 186        # A multi-line entry. The text is sent as one line.
 187        #
 188        /^noddy@my\.domain$/
 189         550 This user is a funny one. You really don't want to send mail to
 190         them as it only makes their head spin.
 191
 192 <b>EXAMPLE HEADER FILTER MAP</b>
 193        /^Subject: make money fast/     REJECT
 194        /^To: friend@public\.com/       REJECT
 195
 196 <b>EXAMPLE BODY FILTER MAP</b>
 197        # First skip over base 64 encoded text to save CPU cycles.
 198        # Requires PCRE version 3.
 199        ~^[[:alnum:]+/]{60,}$~          OK
 200
 201        # Put your own body patterns here.
 202
 203 <b>SEE ALSO</b>
 204        <a href="postmap.1.html">postmap(1)</a>, Postfix lookup table manager
 205        <a href="postconf.5.html">postconf(5)</a>, configuration parameters
 206        <a href="regexp_table.5.html">regexp_table(5)</a>, format of POSIX regular expression tables
 207
 208 <b>README FILES</b>
 209        <a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
 210
 211 <b>AUTHOR(S)</b>
 212        The PCRE table lookup code was originally written by:
 213        Andrew McNamara
 214        andrewm@connect.com.au
 215        connect.com.au Pty. Ltd.
 216        Level 3, 213 Miller St
 217        North Sydney, NSW, Australia
 218
 219        Adopted and adapted by:
 220        Wietse Venema
 221        IBM T.J. Watson Research
 222        P.O. Box 704
 223        Yorktown Heights, NY 10598, USA
 224
 225                                                                  PCRE_TABLE(5)
 226 </pre> </body> </html>