About

A mail delivery agent (MDA) or Mail eXchange ¹⁾ is a SMTP server that is responsible for the local delivery (reception) of e-mail messages to a mailbox

It's also known as:

• message delivery agent (MDA)
• local delivery agent (LDA)
• Mail eXchange (MX)

An MDA gets normally the messages from an MTA (Smtp Server) and delivers them to a mailbox (real or virtual).

Mx record

The email servers IP are set in the DNS via the MX record. This is how a server knows to which server a message should be sent.

For instance, with the email address [email protected], the MTA server will:

• lookup the MX record for the domain name yolo.bar.com,
• connect to the corresponding email server on the port 25
• and transmit the message

Port

The submission port is the port 25.

List

• PostFix
• Dovecot LDA
• wiki/Maildrop (https://wiki.dovecot.org/maildrop)