The destination-header test is the most useful part of this workflow. One detail worth correcting: an explicit sp tag is not required for the organizational domain’s p policy to cover existing subdomains. Under DMARC policy discovery, p is the fallback when no more specific policy overrides it. RFC 9989’s sp definition makes that inheritance explicit. Clarifying this would help readers avoid changing DNS based on the assumption that subdomains are otherwise uncovered.
Mahdi Jabinpour
Building WordPress plugins and AI tools at LumoWP. Practical notes on WooCommerce, performance and multilingual websites.
The destination-header test is the most useful part of this workflow. One detail worth correcting: an explicit sp tag is not required for the organizational domain’s p policy to cover existing subdomains. Under DMARC policy discovery, p is the fallback when no more specific policy overrides it. RFC 9989’s sp definition makes that inheritance explicit. Clarifying this would help readers avoid changing DNS based on the assumption that subdomains are otherwise uncovered.