tcp_table - Postfix client/server table lookup protocol
postmap -q "string" tcp:host:port
postmap -q - tcp:host:port <inputfile
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 sys-
tem supports use the "postconf -m" command.
To test lookup tables, use the "postmap -q" command as
described in the SYNOPSIS above.
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.
Each request specifies a command, a lookup key, and possi-
bly a lookup result.
get SPACE key NEWLINE
Look up data under the specified key.
put SPACE key SPACE value NEWLINE
This request is currently not implemented.
Each reply specifies a status code and text. Replies must
be no longer than 4096 characters including the newline
500 SPACE text 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.
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.
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.
Do not use TCP lookup tables for security critical pur-
poses. The client-server connection is not protected and
the server is not authenticated.
Only the lookup method is currently implemented.
The client does not hang up when the connection is idle
for a long time.
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
DATABASE_README, Postfix lookup table overview
The Secure Mailer license must be distributed with this
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA