Mail delivery agent

Mail delivery agent

A mail delivery agent or message delivery agent (MDA) is a computer software component that is responsible for the delivery of e-mail messages to a local recipient's mailbox.[1] Also called an LDA, or local delivery agent.[2]

Within the 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 mailbox).



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.


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]


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.

List of message delivery agent software for Unix-like platforms

  • binmail, the MDA part of Sendmail
  • deliver
  • fdm - A combined mail retrieval agent and mail delivery agent
  • maildrop
  • postdrop
  • postfix-maildrop - A mail delivery agent for use with the postfix mail transport agent
  • procmail
  • courier-maildrop
  • dovecot - A mail server suite that includes a mail delivery agent
  • dystill - A filtering MySQL database driven mail delivery agent

See also


  1. ^ RFC 5598, Internet Mail Architecture, D. Crocker (July 2009)
  2. ^