Turn MTA-STS back on on Cloudflare

Why it matters

mode: none switches the policy off, so senders go back to delivering mail without requiring TLS. This is normal while retiring MTA-STS but not if you want the protection.

Staged change. Do this in stages and check each one before the next, so a mistake does not break your site or your mail.

The fix

1. Update the policy file (the Worker code or your web host) to mode: testing with your own MX host names in the mx lines, then in DNS > Records edit the _mta-sts TXT record and change the id.
2. Add TLS-RPT, watch the reports, then move to enforce.

Type:     TXT
Name:     _mta-sts.example.com
Content:  v=STSv1; id=2026100502

The examples use example.com. Replace it with your own domain.

Read the documentation ↗(opens in a new tab)

Related

• Reported by the MTA-STS and TLS-RPT check
• Publish an MTA-STS policy, starting in testing mode
• Nothing to do for MTA-STS on a domain that accepts no mail
• Fix the MTA-STS TXT record
• Make the MTA-STS policy file reachable
• Fix the certificate on the MTA-STS policy host
• Fix the MTA-STS policy file
• Switch MTA-STS from testing to enforce
• Make the MTA-STS policy cover every MX host
• Raise the MTA-STS max_age
• Publish a TLS-RPT record
• Fix the TLS-RPT record