Editing Message delivery agent

{{short description|Computer software that delivers email to a mailbox}}
A '''message delivery agent''' ('''MDA'''), or '''mail delivery agent''', is a computer [[software]] component that is responsible for the delivery of [[e-mail]] messages to a local recipient's [[Email Mailbox|mailbox]].<ref>{{IETF RFC|5598}}, ''Internet Mail Architecture'', D. Crocker (July 2009)</ref> It is also called a '''local delivery agent''' ('''LDA''').

Within the [[Internet Mail|Internet mail]] architecture, local message delivery is achieved through a process of handling messages from the message transfer agent, and storing mail into the recipient's environment (typically a [[Email Mailbox|mailbox]]).

==Implementation==

Many mail handling software products bundle multiple message delivery agents with the [[message transfer agent]] component, providing for site customization of the specifics of mail delivery to a user.

[[File:E-mail.svg]]

=== Unix ===

On [[Unix-like]] systems, [[procmail]] and [[maildrop]] are the most popular MDAs.  The [[Local Mail Transfer Protocol]] (LMTP) is a protocol that is frequently implemented by network-aware MDAs.{{Citation needed|date=February 2010}}

==== Invocation ====

The mail delivery agent is generally not started from the command line, but is usually invoked by mail delivery subsystems, such as a [[mail transport agent]], or a [[mail retrieval agent]].

=== Unix-like ===
* [[Cyrus IMAP server|Cyrus IMAP]] - A mail server suite that includes a mail delivery agent
* [[Dovecot (software)|dovecot]] - A mail server suite that includes a mail delivery agent
* [[fetchmail]] - Primarily a [[Mail retrieval agent]] (MRA)
* [[getmail]] - simpler, more secure, modern [[fetchmail]] alternative
* [[fdm (software)|fdm]] — modern replacement for both [[fetchmail]] and [[procmail]] from the author of [[tmux]]
* [[maildrop]] or courier-maildrop - traditional procmail replacement, part of [[Courier Mail Server]], but can also be used with other mail servers
* [[procmail]] - old, but still used
* bin/mail, the MDA part of [[Sendmail]] - Sendmail is one of the oldest email packages
* [[Sieve (mail filtering language)|Sieve mail filtering language]] - a standardised mail filtering language; also, a modern replacement for procmail from the [[GNU Mailutils]] package

==See also==
* [[Message transfer agent]] (MTA)
* [[Mail retrieval agent]] (MRA)
* [[Message submission agent]] (MSA)
* [[Message user agent]] (MUA) a.k.a. email client
* [[E-mail agent (infrastructure)]] (MxA)

==References==
{{reflist}}

{{DEFAULTSORT:Mail Delivery Agent}}
[[Category:Mail delivery agents|*]]