What is a mail server?
A mail server (sometimes called MTA – Mail Transport Agent) is an application that is used to transfer mails from one user to another. A mail server handles both sending and receiving mails using protocols such as SMTP (Simple Mail Transfer Protocol) or ESMTP (Extended SMTP) for sending mails and POP3 (Post Office Protocol 3) or IMAP (Internet Message Access Protocol) for receiving mails.
