2. EL 7
  3. postfix
  4. cidr_table(5)

Scroll to navigation

CIDR_TABLE(5) File Formats Manual CIDR_TABLE(5)

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:



  

  
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.

  

  

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

  

  
Empty lines and whitespace-only lines are ignored, as are lines whose
      first non-whitespace character is a `#'.

  

  
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