DNS 2 SERVFAIL vs 9 NOTAUTH
Both DNS 2 (SERVFAIL) and 9 (NOTAUTH) 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, 9 means that server Not Authoritative for zone, or Not Authorized. The server is not authoritative for the zone named in the Zone section.
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.
説明
Server Not Authoritative for zone, or Not Authorized. The server is not authoritative for the zone named in the Zone section.
このコードが表示される場合
You sent a dynamic update or zone operation to a server that is not the authoritative master for that zone, or the server rejected it due to TSIG authentication failure.
解決方法
Send the update to the correct primary authoritative server for the zone. If using TSIG, verify the key name and secret match on both client and server.
主な違い
DNS 2: Server failure. The name server encountered an internal error while processing the query.
DNS 9: Server Not Authoritative for zone, or Not Authorized. The server is not authoritative for the zone named in the Zone section.
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 9 when you sent a dynamic update or zone operation to a server that is not the authoritative master for that zone, or the server rejected it due to TSIG authentication failure.
どちらをいつ使うか
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 9 (NOTAUTH): Send the update to the correct primary authoritative server for the zone. If using TSIG, verify the key name and secret match on both client and server.