DNS 2 SERVFAIL vs 3 NXDOMAIN
Both DNS 2 (SERVFAIL) and 3 (NXDOMAIN) belong to the DNS Response Codes (RCODEs) category. 2 indicates that server failure. The name server encountered an internal error while processing the query. Meanwhile, 3 means that non-Existent Domain. The queried domain name does not exist in the DNS namespace.
描述
Server failure. The name server encountered an internal error while processing the query.
何时出现
The recursive resolver could not get an authoritative answer — commonly caused by DNSSEC validation failures, unreachable upstream nameservers, or misconfigured zones.
如何修复
Try a different resolver (e.g., 8.8.8.8 or 1.1.1.1) to isolate the issue. If you control the zone, check DNSSEC signatures, SOA serial consistency, and nameserver reachability.
描述
Non-Existent Domain. The queried domain name does not exist in the DNS namespace.
何时出现
The domain has no DNS records at all — either it was never registered, has expired, or you have a typo in the hostname.
如何修复
Double-check the domain spelling. If you own the domain, verify your registrar settings and ensure the nameservers are correctly delegated.
主要区别
DNS 2: Server failure. The name server encountered an internal error while processing the query.
DNS 3: Non-Existent Domain. The queried domain name does not exist in the DNS namespace.
You encounter 2 when the recursive resolver could not get an authoritative answer — commonly caused by DNSSEC validation failures, unreachable upstream nameservers, or misconfigured zones.
You encounter 3 when the domain has no DNS records at all — either it was never registered, has expired, or you have a typo in the hostname.
何时使用哪个
For 2 (SERVFAIL): Try a different resolver (e.g., 8.8.8.8 or 1.1.1.1) to isolate the issue. If you control the zone, check DNSSEC signatures, SOA serial consistency, and nameserver reachability. For 3 (NXDOMAIN): Double-check the domain spelling. If you own the domain, verify your registrar settings and ensure the nameservers are correctly delegated.