A Mail Delivery Agent (MDA) is software that accepts incoming e-mail messages and distributes them to recipients' individual mailboxes (if the destination account is on the local machine), or forwards back to an SMTP server (if the destination is on a remote server).

A mail delivery agent is not necessarily a mail transfer agent (MTA), although on many systems the two functions are implemented by the same program.

On unix systems, /bin/mail is the most popular MDA.

See also: mail user agent (MUA).

Mail Delivery Agent | Mail Delivery Agent | メール配送エージェント | MDA (poczta) | MDA