When A Name Will Not Resolve
DNS failures are sneaky because the application just reports it cannot connect. DNS resolution debugging means tracing the lookup step by step to find where the name fails or returns the wrong address.
The Chain Of Resolution
A lookup passes through several stages, any of which can break.
- The host first checks a local file and any cache before asking the network.
- A resolver is queried, which may walk from the root to the authoritative server.
- The authoritative server holds the true record for the zone.
A wrong answer early in this chain is served as if it were correct.
Pinpointing The Fault
Query the record type directly and compare what your local resolver returns against the authoritative server. A mismatch usually means a stale cache somewhere in the middle. Check the time to live to judge how long a bad answer can linger. Remember that the host file and search domains can silently override or reshape a name before any network query happens.
Key idea
DNS resolution debugging traces a lookup from the local cache and host file through the resolver to the authoritative server, and comparing the local answer with the authoritative one exposes stale caches or local overrides.