A dmarcian.com user once asked:
I can't seem to find the answer to this question anywhere on the Internet (it may just be me not fully understanding the standards), so I thought I'd ask you. If I have DMARC set up in my DNS (which I do) and also ADSP (also do), which one takes precedence? I'm also assuming that I am in overkill mode and that DMARC is enough. Your input would be appreciated when you have a moment.
- No one implements ADSP. It is dead tech.
- DMARC is considered by most to be a superset of ADSP. See section "A.5. Issues With ADSP In Operation" of RFC 7489.
Given the above, we suggest removing your ADSP records to prevent the few sites that do implement it from doing the wrong thing.