3. Publish your MTA-STS policy

After creating your policy, upload the file to a public web server where remote servers can access it.

Host server requirements

The web server that hosts your policy must meet these requirements:

• Supports SSL/HTTPS.
• Server certificate is signed and trusted by a third-party root certificate authority.

Policy changes

Every time you change the contents of the policy file, you must:

• Update the policy file on the public web server.
• Change the policy ID in the DNS records. Learn more at Turn on MTA-STS and TLS reporting.

You must also take these steps when changing a policy from testing mode to enforced mode.

Add policy to a web server in your domain

1. Verify that your domain is set up with a public web server.
2. Add a subdomain to your domain. The subdomain name must start with mta-sts, for example:
   mta-sts.solarmora.com
3. Create a directory named .well-known in the subdomain.
4. Upload the policy file you created to the .well-known directory.

   An example URL for an MTA-STA policy is:
   https://mta-sts.solarmora.com/.well-known/mta-sts.txt

Next Steps

Turn on MTA-STS and TLS reporting