DNS 0 NOERROR vs 2 SERVFAIL
Both DNS 0 (NOERROR) and 2 (SERVFAIL) belong to the DNS Response Codes (RCODEs) category. 0 indicates that no error condition. The query completed successfully and the response contains the requested data. Meanwhile, 2 means that server failure. The name server encountered an internal error while processing the query.
説明
No error condition. The query completed successfully and the response contains the requested data.
このコードが表示される場合
This is the normal, successful response to any DNS query — the name was resolved and the answer section contains the requested records.
解決方法
No fix needed. RCODE 0 means the DNS lookup succeeded as expected.
説明
Server failure. The name server encountered an internal error while processing the query.
このコードが表示される場合
The recursive resolver could not get an authoritative answer — commonly caused by DNSSEC validation failures, unreachable upstream nameservers, or misconfigured zones.
解決方法
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.
主な違い
DNS 0: No error condition. The query completed successfully and the response contains the requested data.
DNS 2: Server failure. The name server encountered an internal error while processing the query.
You encounter 0 when this is the normal, successful response to any DNS query — the name was resolved and the answer section contains the requested records.
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.
どちらをいつ使うか
For 0 (NOERROR): No fix needed. RCODE 0 means the DNS lookup succeeded as expected. 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.