Topic: dns
-
DNS records a web service depends on
A, AAAA and CNAME map names to addresses, MX routes mail, TXT carries verifications and policies, CAA restricts certificate issuers, NS delegates zones; check authoritative answers, not only a cached resolver, before and after changes.
-
Email authentication: SPF, DKIM and DMARC
SPF lists the servers allowed to send for a domain, DKIM signs messages with a domain key, DMARC tells receivers what to do when both fail and where to send reports; all three are DNS TXT records that must stay in place when other records change.
Machine-readable: JSON