Best for listing record types, reading TTLs, checking mail policies and confirming the normal answer from a known resolver.
Best after a DNS change, during an incident or when users in different regions report different results.
Use both during a migration
Start with a complete DNS lookup to confirm the authoritative record is correct. Then sample multiple locations. If probes disagree, compare their TTLs and resolver answers rather than treating every difference as a failure.
What neither test proves
Neither test reaches every recursive resolver, and neither identifies a hidden origin behind a proxy. They report the public DNS evidence available from their selected resolver or probe network.