Host
_mta-sts.domain.com
Data
v=STSv1; id=20250910
Update the id when the policy is changed.
Host
_smtp._tls.domain.com
Data
v=TLSRPTv1; rua=mailto:tlsrpt@domain.com
Host
mta-sts.domain.com
Ensure the URL is accessible after deployment:
https://mta-sts.domain.com/.well-known/mta-sts.txt