A mail transfer agent (MTA) is a program that runs on a server to transfer emails between the sender’s computer and the recipient’s computer. It plays an important role in the internet message handling system, which includes core tasks like email queueing, throttling, connection management, scheduling, data transfer, bond generation, deferrals processing, and delivery status tracking.
MTA does the background work through back-end server applications, however, the user interacts with the email marketing tool, not with the MTA interface.
Mail transfer agents use a store-and-forward model to handle emails; the outgoing email will be stored in a queue, and they will wait for the response from the recipient server. If the MTA gets the response during the established term, the email will be sent, but if not, the email will fail to be delivered and returned to the mail client.
If the MTA is configured correctly, it can have a great impact on email deliverability and can enhance the performance of the email marketing tool.
Things to Consider When Choosing a Mail Transfer Agent
When choosing a mail transfer agent, it is best to make your decision based on resources and goals; however, the two aspects discussed below are of utmost priority.
- MTA’s Configurability: A good mail transfer agent should give you access to specific configurations so you can improve the performance of the MTA. For example, you should be able to enable authentication, set up multiple mail queues, troubleshoot in real time and so on.
- MTA’s Performance: This involves the volumes, speed, and latency of sending emails; a dedicated MTA should provide full control over these sending parameters and also allow you to monitor analytics and performance.
Must-Have Features for a Reliable Mail Transfer Agent
- Multiple queuing.
- Clustering.
- API/integration.
- Email authentication capability and monitoring (SPF, DKIM, DMARC).
- Deliverability features like routing rules, throttling, IP pools, etc.
- Spam control.
- Migration ability and scalability.
- Security policy and data protection mechanisms.
- User-friendly pricing and infrastructure transparency.
- User support for troubleshooting.