Mail Transfer Agent Strict Transport Security (MTA-STS) is a protocol that aims to strengthen the security of inbound emails. By ensuring that your inbound emails are properly encrypted, MTA-STS provides a secure experience while delivering emails to your inbox. As a result, it helps businesses and individuals to protect their emails from potential malicious interception and tampering.
Why Implement It?
By default, the traditional Simple Mail Transfer Protocol (SMTP) does not enforce encryption.
MTA-STS comes to address this vulnerability.
To prevent interception in the transit process, MTA-STS ensures secure encryption by Transport Layer Security (TLS). By requiring a secure TLS connection, MTA-STS mitigates the risk of Man-in-the-Middle (MITM).
Moreover, MTA-STS mandates that only servers with valid publicly-trusted certificates can deliver emails to your domain. This significantly lowers the risk associated with expired or invalid certificates.
Gmail, Outlook, and many other major providers have adopted MTA-STS, making it a widely accepted and supported standard.
How Does It Work?
Here’s how MTA-STS works:
You need to publish a DNS TXT record under _mta-sts.<yourdomain> to indicate that your domain uses MTA-STS.
This TXT record includes the version of the policy and specifies whether it’s enforced or just in testing mode (policy modes: enforce or testing).
You also need an HTTPS-hosted policy file, which is referenced indirectly through this TXT record.
The MTA-STS policy file must be hosted on a web server over HTTPS at https://mta-sts.<yourdomain>/.well-known/mta-sts.txt.
This file includes details like the minimum required TLS version, supported MX hosts, and conditions for valid TLS certificates.
Before delivering emails, the sending mail server retrieves and verifies the MTA-STS policy file.
Suppose the recipient server fails to meet the policy requirements (e.g., outdated TLS version, invalid certificates, or missing secure connections). In that case, the sending server will fail to deliver the email when the policy is set to enforce.
By enforcing MTA-STS, you can ensure that emails are transmitted securely and prevent interception by malicious entities.
Get Started Now!
Before you jump to the full adoption of MTA-STS, you can start with MTA-STS “Testing.” This will provide you with the correct configurations without adversely impacting your email delivery.
After you successfully implement the MTA-STS Testing mode and everything is up and running smoothly, you can aim for full protection with the “Enforce” mode. This will ensure the secure transmission of your emails and an improved overall email security infrastructure. For more detailed information, read our complete guide on MTA-STS.
With PowerDMARC, full protection with MTA-STS will be achieved faster and more efficiently, enabling you to reach enhanced security in less than no time! Contact us to learn more.