In the evolving landscape of the Internet, email, as a medium for communication, has become increasingly vulnerable to various security threats. Ensuring secure mail transfers is paramount, particularly for businesses that handle sensitive information. In this regard, MTA-STS (Mail Transfer Agent Strict Transport Security) and TLS (Transport Layer Security) reporting play a critical role. By enhancing email server security, these mechanisms provide comprehensive protection against interception and manipulation of email traffic.

How to enable MTA policies for your mail server

MTA-STS is a relatively new standard that enables mail service providers to declare their ability to secure SMTP connections and specify policies that other sending servers should abide by when delivering email. On the other hand, TLS reporting allows mail servers to send reports to the domain owner about the success or failure of secure connections. Implementing these protocols can significantly augment your mail server security. Here's how to configure it for your server:

Step 1: Setting Up MTA-STS Policy

MTA-STS policies are text files hosted on a subdomain (mta-sts) over HTTPS. The policy file should include the following key elements: version, mode, and MX. The 'version' specifies the MTA-STS standard version used (typically "STSv1"), 'mode' can be set to 'testing', 'enforce', or 'none' depending on the phase of implementation, and 'MX' defines the mail servers that should adhere to this policy.

Step 2: Publishing MTA-STS Policy

After setting up your policy, the next step is to publish it. You will need to create a TXT record in your DNS with the name _mta-sts, containing the id of your policy (any alphanumeric string). This informs other MTAs that your domain supports MTA-STS and where they can find the policy.

Step 3: Enabling TLS Reporting

To enable TLS reporting, you'll need to publish another DNS TXT record, this time with the name _smtp._tls. The record should contain a 'v=TLSRPTv1' tag indicating the version of TLS reporting being used, and a 'rua=' tag specifying where aggregate reports should be sent.

While the implementation process may seem intricate, the benefits it provides in terms of enhanced security far outweigh the technicalities involved.

Why is Implementing MTA-STS and TLS Reporting Important?

  1. Prevents Man-in-the-Middle Attacks: MTA-STS and TLS help to prevent man-in-the-middle attacks by enforcing encrypted connections. These attacks can lead to significant data leaks, which MTA-STS and TLS effectively guard against.

  2. Boosts Email Deliverability: Using MTA-STS can boost your email deliverability rate. Many email providers prioritize emails from domains that implement modern security standards.

  3. Monitors Connection Security: TLS reporting allows domain owners to receive reports about the successful or unsuccessful establishment of secure connections. This provides insight into potential security issues and allows for swift responses to any detected threats.

  4. Promotes Trust: Having a secure email server can increase trust among your users or clients. In a world where data breaches are becoming increasingly common, securing your email server could provide a competitive edge.

To sum up, implementing MTA-STS and TLS reporting is a must-have for any mail server. By doing so, you not only upgrade your security measures but also improve your service's reliability and trustworthiness. It may require an initial investment of time and effort, but the peace of mind knowing that your emails are secure makes it a worthwhile endeavor.

Secure email with MailSlurp

MailSlurp email APIs support MTA-STS out of the box so your emails will enjoy high deliverability and stellar sender reputations. For more help with enabling MTA STS polices see our mailserver tools page. To enable MTA-STS and TLS reporting in SES see this excellent AWS blog post.