Suggestion: Generate DMARC authorization
When a DMARC DNS record is created in a zone, and the MX domain is hosted locally, create a DMARC record in the mail server domain.
Example: Hostname = foo.tld, MX mailserver hostmame = mail.bar.com
When we create this in zone foo.tld:
_dmarc.foo.tld. TXT v=DMARC1; p=reject; rua=mailto:email@example.com; ruf=mailto:firstname.lastname@example.org; fo=0:1:d:s
Generate this in zone bar.com:
foo.tld._report._dmarc.bar.com. TXT v=DMARC1;
It must be verified that bar.com is a locally defined zone, and that the mailto value (email@example.com) is an active address.