The LMTP class
RFC 2033 defines the Local Mail Transport Protocol. In many ways, this is very similar to SMTP, but with no guarantees of queuing. It is, in a sense, an alternative to ESMTP, and is often used for local mail routing (e.g. from a Mail Transport Agent to a local command or system) where the unreliability of internet connectivity is not an issue.
The LMTP
class subclasses the SMTP
class
and its only functional difference is that
it implements the LHLO
command,
and prohibits the use of HELO
and EHLO
.