<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <title> Postfix manual - tcp_table(5) </title> </head> <body> <pre> TCP_TABLE(5) TCP_TABLE(5) <b>NAME</b> tcp_table - Postfix client/server table lookup protocol <b>SYNOPSIS</b> <b>postmap -q "</b><i>string</i><b>" <a href="tcp_table.5.html">tcp</a>:</b><i>host:port</i> <b>postmap -q - <a href="tcp_table.5.html">tcp</a>:</b><i>host:port</i> <<i>inputfile</i> <b>DESCRIPTION</b> The Postfix mail system uses optional tables for address rewriting or mail routing. These tables are usually in <b>dbm</b> or <b>db</b> format. Alterna- tively, table lookups can be directed to a TCP server. To find out what types of lookup tables your Postfix system supports use the "<b>postconf -m</b>" command. To test lookup tables, use the "<b>postmap -q</b>" command as described in the SYNOPSIS above. <b>PROTOCOL DESCRIPTION</b> 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. <b>REQUEST FORMAT</b> Each request specifies a command, a lookup key, and possibly a lookup result. <b>get</b> SPACE <i>key</i> NEWLINE Look up data under the specified key. <b>put</b> SPACE <i>key</i> SPACE <i>value</i> NEWLINE This request is currently not implemented. <b>REPLY FORMAT</b> Each reply specifies a status code and text. Replies must be no longer than 4096 characters including the newline terminator. <b>500</b> SPACE <i>text</i> NEWLINE In case of a lookup request, the requested data does not exist. In case of an update request, the request was rejected. The text describes the nature of the problem. <b>400</b> SPACE <i>text</i> NEWLINE This indicates an error condition. The text describes the nature of the problem. The client should retry the request later. <b>200</b> SPACE <i>text</i> NEWLINE The request was successful. In the case of a lookup request, the text contains an encoded version of the requested data. <b>ENCODING</b> 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 hexadec- imal 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. <b>SECURITY</b> Do not use TCP lookup tables for security critical purposes. The client-server connection is not protected and the server is not authen- ticated. <b>BUGS</b> Only the lookup method is currently implemented. The client does not hang up when the connection is idle for a long time. <b>SEE ALSO</b> <a href="postmap.1.html">postmap(1)</a>, Postfix lookup table manager <a href="regexp_table.5.html">regexp_table(5)</a>, format of regular expression tables <a href="pcre_table.5.html">pcre_table(5)</a>, format of PCRE tables <a href="cidr_table.5.html">cidr_table(5)</a>, format of CIDR tables <b>README FILES</b> <a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview <b>LICENSE</b> The Secure Mailer license must be distributed with this software. <b>AUTHOR(S)</b> 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) </pre> </body> </html>