bionic (5) tcp_table.5.gz

Provided by: postfix_3.3.0-1ubuntu0.4_amd64 bug

NAME

       tcp_table - Postfix client/server table lookup protocol

SYNOPSIS

       postmap -q "string" tcp:host:port

       postmap -q - tcp:host:port <inputfile

DESCRIPTION

       The  Postfix  mail  system  uses  optional tables for address rewriting or mail routing. These tables are
       usually in dbm or db format. Alternatively, table lookups can be directed to a TCP server.

       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.

PROTOCOL DESCRIPTION

       The TCP map class implements a very simple protocol: the client sends a request, and the server sends one
       reply.  Requests  and  replies  are  sent  as  one  line  of  ASCII text, terminated by the ASCII newline
       character. Request and reply parameters (see below) are separated by whitespace.

       Send and receive operations must complete in 100 seconds.

REQUEST FORMAT

       The tcp_table protocol supports only the lookup request.  The request has the following form:

       get SPACE key NEWLINE
              Look up data under the specified key.

       Postfix will not generate partial search keys such as  domain  names  without  one  or  more  subdomains,
       network addresses without one or more least-significant octets, or email addresses without the localpart,
       address extension or domain portion. This behavior is also found with cidr:, pcre:, and regexp: tables.

REPLY FORMAT

       Each reply specifies a status code and text. Replies must be no longer than 4096 characters including the
       newline terminator.

       500 SPACE text NEWLINE
              In  case of a lookup request, the requested data does not exist.  The text describes the nature of
              the problem.

       400 SPACE text NEWLINE
              This indicates an error condition. The text describes the nature of the problem. The client should
              retry the request later.

       200 SPACE text NEWLINE
              The  request was successful. In the case of a lookup request, the text contains an encoded version
              of the requested data.

ENCODING

       In request and reply parameters, the character  %,  each  non-printing  character,  and  each  whitespace
       character  must  be replaced by %XX, where XX is the corresponding ASCII hexadecimal character value. The
       hexadecimal codes can be specified in any case (upper, lower, mixed).

       The Postfix client always encodes a request.  The server may omit the encoding as long as  the  reply  is
       guaranteed to not contain the % or NEWLINE character.

SECURITY

       Do  not  use  TCP  lookup  tables  for  security  critical purposes.  The client-server connection is not
       protected and the server is not authenticated.

BUGS

       Only the lookup method is currently implemented.

       The client does not hang up when the connection is idle for a long time.

SEE ALSO

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

README FILES

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

LICENSE

       The Secure Mailer license must be distributed with this software.

AUTHOR(S)

       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA

                                                                                                    TCP_TABLE(5)