Introduction

A mail delivery agent or message delivery agent (MDA) is computer software that transfers the responsibility for the management of e-mail messages from the message transfer agent (MTA) within the message handling service (MHS) to a recipient's environment, commonly transferring them into a mailbox.

Within the Internet mail architecture, message delivery agents consist of two components, the message handling service side that accepts messages from the message transfer agent, and a component in the recipient's environment that affects message storage in a mailbox or other customized mechanisms.

References

1. http://en.wikipedia.org/wiki/Mail_delivery_agent