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MTA-STS Checker
Check whether your domain enforces encrypted mail connections with MTA-STS.
Analysis messages from the checker are currently in Dutch.
How does it work?
MTA-STS tells sending mail servers to connect to your mail server over TLS only. It consists of a DNS record at _mta-sts and a policy file at mta-sts.yourdomain.com. We check both.
Frequently asked questions
What is the difference between testing and enforce?
In testing a sender only reports problems, in enforce mail that cannot be encrypted is rejected. Start with testing.
Do I need MTA-STS with Microsoft 365?
It is not mandatory, but it protects against interception in transit and fits NIS2 measures.
What is TLS-RPT?
A complementary record that lets receivers report failed TLS connections to you.
Need help with your email security?
We set up DMARC, SPF, DKIM and MTA-STS for you and keep an eye on it, as part of Security and Monitoring.