Provided by: postfix_2.9.1-4_amd64 bug

NAME

       cidr_table - format of Postfix CIDR tables

SYNOPSIS

       postmap -q "string" cidr:/etc/postfix/filename

       postmap -q - cidr:/etc/postfix/filename <inputfile

DESCRIPTION

       The  Postfix  mail system uses optional lookup tables.  These tables are usually in dbm or
       db format.  Alternatively, lookup tables can be specified in CIDR (Classless  Inter-Domain
       Routing)  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 "postconf -m"
       command.

       To test lookup tables, use the "postmap -q" command as described in the SYNOPSIS above.

TABLE FORMAT

       The general form of a Postfix CIDR table is:

       network_address/network_mask     result
              When  a  search  string  matches the specified network block, use the corresponding
              result value. Specify 0.0.0.0/0 to match every IPv4  address,  and  ::/0  to  match
              every IPv6 address.

              An  IPv4 network address is a sequence of four decimal octets separated by ".", and
              an IPv6 network address is a sequence of three to  eight  hexadecimal  octet  pairs
              separated by ":".

              Before  comparisons  are  made,  lookup  keys  and table entries are converted from
              string to binary. Therefore table entries will be matched regardless  of  redundant
              zero characters.

              Note:  address  information  may  be  enclosed  inside  "[]"  but  this form is not
              required.

              IPv6 support is available in Postfix 2.2 and later.

       network_address     result
              When a search string matches the specified network address, use  the  corresponding
              result value.

       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 logical line.

TABLE SEARCH ORDER

       Patterns are applied in the order as specified in the table, until a pattern is found that
       matches the search string.

EXAMPLE SMTPD ACCESS MAP

       /etc/postfix/main.cf:
           smtpd_client_restrictions = ... cidr:/etc/postfix/client.cidr ...

       /etc/postfix/client.cidr:
           # Rule order matters. Put more specific whitelist entries
           # before more general blacklist entries.
           192.168.1.1             OK
           192.168.0.0/16          REJECT

SEE ALSO

       postmap(1), Postfix lookup table manager
       regexp_table(5), format of regular expression tables
       pcre_table(5), format of PCRE tables

README FILES

       Use "postconf readme_directory" or "postconf html_directory" to locate this information.
       DATABASE_README, Postfix lookup table overview

HISTORY

       CIDR table support was introduced with Postfix version 2.1.

AUTHOR(S)

       The CIDR table lookup code was originally written by:
       Jozsef Kadlecsik
       KFKI Research Institute for Particle and Nuclear Physics
       POB. 49
       1525 Budapest, Hungary

       Adopted and adapted by:
       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA

                                                                                    CIDR_TABLE(5)