< messaging , protocol > (LMTP) A protocol designed as an alternative to ESMTP for cases where the mail receiver does not manage a queue. LMTP is an application level protocol that runs on top of TCP/IP . It was initially defined in RFC 2033 , and uses (with a few changes) the syntax and semantics of ESMTP . It should be used only by specific prior arrangement and configuration, and it must not be used on TCP port 25 (the SMTP port).
(2002-03-09)