A Mail Transfer Agent (MTA) is a software application or program responsible for routing and delivering email messages across a network.
When you send an email, your email client (such as Outlook or
Gmail) communicates with the MTA to send the message to the recipient's email server. The MTA transfers the email from one server to another, ensuring it reaches the intended mailbox.
MTAs use standard email protocols such as Simple Mail Transfer Protocol (SMTP) to send and receive emails.
They receive incoming messages, perform various checks (such as
spam filtering and virus scanning), and then deliver them to the appropriate recipient's mailbox. Similarly, when sending an outgoing email, it connects to the recipient's email server, delivers the message, and handles any errors or delivery failures that may occur.
In addition to message routing and delivery, they often provide other features like authentication, encryption, and message queuing. They may also have built-in spam filtering, anti-virus scanning, and support for various email protocols and standards.