About
A Mail eXchange (MX) is a smtp server that is responsible for :
- receiving emails for one or more domain
- and delivering them to a mail delivery agent (MDA) for final delivery
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
Port
The reception port is the port 25.