Acronym: Mail–Transfer Agent
An MTA in a program which runs on a server, waiting for TCP connections from other computers. It uses the SMTP protocol. The MTA waits till a client connects to it and asks it to send an e-mail to an e-mail addresss. The MTA, using DNS MX records, then figures out to which MTA it should send the e-mail to. When the MTA receives the mail it writes it into the users’ mailbox after which a MUA can pick it up using the POP3 protocol, the IMAP protocol or by direct access via a shell.
- Sendmail – The first and still most popular MTA. Often also regarded as the most insecure.
- Postfix – Wietse Venema’s MTA.
- Qmail – DJB‘s MTA.
TakeDown.NET -> “MTA”