6 min readDNS Lookup
How to Look Up DNS Records When Something Breaks
Use A, AAAA, MX, TXT, CNAME, and NS lookups to debug domains, email, and website migrations.
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Start with the record type you need
DNS answers different questions with different record types. Website traffic usually depends on A or AAAA records, email depends on MX, and verification or SPF settings often live in TXT.
- A / AAAA: where the domain points
- MX: which mail servers receive email
- TXT: verification, SPF, DKIM, and other text policies
- CNAME: aliases to another hostname
- NS: which nameservers are authoritative
Watch TTL and propagation
TTL tells resolvers how long to cache an answer. After a DNS change, some networks will still see the old value until their cache expires. That is why migrations can look inconsistent for a while.
Debug with a clear checklist
Confirm the domain spelling, check the relevant record type, compare the result with what you expected to publish, and re-check after waiting for TTL if needed.