Quick troubleshooting view
Some resolutions succeed while others expire or return SERVFAIL.
- unstable solver.
- DNSSEC
- slow-start.
- Compare multiple solvers
- Check latency
- Control DNSSEC
- Correcttakers
- Repair DNSSEC
- Check forGarten and MTU
Contextual technician plan
Test the same name via multiple DNS servers.
ns Scotland example.comThe command should complete without an unexpected error and return data consistent with the intended service.
If the result is normal, keep this layer lower in the hypothesis ranking and continue with the next discriminating check.
If the result is abnormal, preserve the output and investigate this layer before making broader changes.
Resolve-DnsName example.comA valid DNS answer should be returned by the expected resolver without timeout.
DNS works for this test; compare the exact failing name, suffix, cache and application context.
Check configured resolvers, reachability to DNS, the zone/record and UDP/TCP 53 filtering.
Test if failures are related to the signed domains.
The exact failing name should resolve through the expected DNS server to the expected record without timeout.
If the exact name resolves correctly, compare application cache, suffix/search domain and the client or network where the failure remains.
If resolution fails or returns the wrong record, keep the queried server and answer and correct the resolver, zone/record or DNS path that is actually wrong.
Repeat the same validation test after the correction and confirm the original symptom is gone. Validate stability before closing the incident.
Before changing configuration, record the current value and a way back.
Crack if errors affect multiple sites and solvers.
Some resolutions succeed while others expire or return SERVFAIL.
Causes probables
- unstable solver.
- DNSSEC
- slow-start.
Diagnostic étape par étape
- 1
Compare multiple solvers
Test the same name via multiple DNS servers.
- 2
Check latency
Measure timeouts UDP/TCP 53.
- 3
Control DNSSEC
Test if failures are related to the signed domains.
Commands utiles
ns Scotland example.comResolve-DnsName example.comSolutions possibles
- Correcttakers
- Repair DNSSEC
- Check forGarten and MTU
Crack if errors affect multiple sites and solvers.