F=z
Deliver with LMTP V8.9 and later
The LMTP protocol (documented in RFC2033) is a language similar to SMTP, but it is used to deliver messages to a program that does local, final delivery. LMTP uses an acknowledged protocol that allows each recipient’s status to be reported individually, avoiding some of the problems of nonacknowledged delivery.
The F=z
delivery
agent flag causes the delivery agent to speak LMTP
to the invoked delivery program. This delivery agent
flag should be set only when an appropriate program
is used. The easy way to use LMTP is described in
the section dealing with FEATURE(local_lmtp)
(FEATURE(local_lmtp) on page 625). FEATURE(local_lmtp)
uses the
mail.local program that is
supplied with the open source
sendmail distribution. (See
The mail.local Delivery Agent on
page 359 for a full description of the
mail.local program, and its
various switches that can modify how it uses
LMTP.)
Note that declaring FEATURE(local_lmtp)
causes this
F=z
delivery
agent flag to be automatically included for the
local
delivery
agent (as well as F=X
, F=X
on page 782).
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