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Exoprise Glossary

Mail Transfer Agent (MTA)

What is Mail Transfer Agent?

Mail Transfer Agent or MTA is an application or component responsible for routing and transferring of emails between mail servers. They are critical in the process of delivering mail by making sure messages a relayed properly between the sender and receivers email servers.

Here is a basic overview of how Mail Transfer Agents function:

Sender’s MTA:

When users send emails, the email client communicates with the MTA on the sender’s mail server. This MTA is responsible for accepting the message and its delivery process.


The sender’s MTA identifies the route to the receiving mail server based on the receiving email address. It then uses Domain Name System (DNS) to look up the mail exchange (MX) records which identifies the mail server responsible for receiving the emails.

Message Transfer:

The sender’s MTA establishes the connection to the recipient’s mail server then transfers the message. This typically occurs using Simple Mail Transfer Protocol (SMTP), a standard for email communications.

Recipient’s MTA:

The recipient’s MTA receives the message and stores it into the mailbox of the recipient or to other components responsible for further processing, such as a mail delivery agent.

MTAs ensure reliable transfer of emails across the internet. They help facilitate communications between different organizations domains and email servers while having a critical role in the infrastructure of emails. MTAs help with managing the complex routing and delivery in a timely and accurate.

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