About
A mail transfer agent or MTA 1) is a SMTP server that receives an email and transmits it to its final destination, the Mail Delivery Agent SMTP server.
MTA is also known as:
- message transfer agent.
- or SMTP relay
Basic
If you want to know the base of email, see this page: How does the email system work? SMTP, POP, IMAP explained
Transport / Transmission
An MTA may transport the E-Mail messages:
| Transport Type | Description |
|---|---|
| remotely | to another server MTA |
| locally | to the Local Delivery Agent (MDA/LDA (that write them into the mailbox) |
List
Server
The well-known MTA that you would install on your server are:
- Exim (developed at the University of Cambridge)
Client
Client MUAs (such as mutt, thunderbird, sylpheed, evolution, kmail) hand off newly sent messages to an MTA. 2)