LMTP channels

LMTP over TCP/IP channels are a special case of TCP/IP channels. The MTA&#x27;s LMTP channels come in two varieties, LMTP client and  LMTP server. (Unlike the MTA&#x27;s general SMTP over TCP/IP channels which are often configured for bidirectional use, the MTA&#x27;s LMTP channels are each dedicated to either client or server operation, the LMTP client channels operating on "front end" MTAs to transmit via LMTP over TCP/IP to back end Message Store systems, and the LMTP server operating on back end Message Store systems to deposit messages into the Message Store.)

The MTA&#x27;s LMTP server operates as a sort of combination of the MTA&#x27;s SMTP server, and the  channel (the delivery into the Message Store portion of the   channel). In particular, the IMAP error statuses that can be encountered by the   channel, discussed further in ims-ms channel error messages, also are relevant for the LMTP server (and indeed, since the LMTP server in turn passes such errors back in the form of SMTP error responses to  the LMTP client, they are reported to the LMTP client also).

See also:
 * Channels
 * lmtp Option
 * Available channels
 * TCPIP channels
 * Typical TCPIP channels and servers
 * IMAP error statuses
 * ims-ms channel error messages
 * LMTP client TCPIP channels
 * LMTP back end TCPIP channel