Overview
DNS answers where a hostname should resolve. Correct records are the start of onboarding, not a replacement for HTTPS, origin or application configuration.
Resolution involves several roles
Recursive resolvers look up and cache answers for clients; authoritative servers publish records for a zone. Distinguish an updated authoritative record from a resolver still using a cached answer.
Choose records by purpose
A and AAAA records provide addresses, CNAME records alias names, MX records direct mail, and TXT records support uses such as verification. Use the actual onboarding target rather than inventing one from an example.
- Check the name, type, target and conflicting records
- Preserve mail and ownership-verification records
- Check provider support before changing the zone apex
TTL affects caching, not instant propagation
TTL tells resolvers how long an answer may be cached. Lowering it ahead of migration can help, but previously cached answers may remain valid. Allow overlap between the old and new service paths.
Verify beyond DNS
Compare authoritative and recursive answers, then test certificates, host routing and real pages at the target. A successful lookup provides an answer; it does not prove the application is healthy.