DNS 2 SERVFAIL vs 4 NOTIMP
Both DNS 2 (SERVFAIL) and 4 (NOTIMP) 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, 4 means that not Implemented. The name server does not support the requested query type or operation.
विवरण
Server failure. The name server encountered an internal error while processing the query.
जब आप इसे देखें
The recursive resolver could not get an authoritative answer — commonly caused by DNSSEC validation failures, unreachable upstream nameservers, or misconfigured zones.
कैसे ठीक करें
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.
विवरण
Not Implemented. The name server does not support the requested query type or operation.
जब आप इसे देखें
You sent a query type (e.g., IXFR, dynamic update) that the server does not support or has disabled.
कैसे ठीक करें
Verify the server supports the query type you are using. If you need zone transfers or dynamic updates, enable them in the server configuration.
मुख्य अंतर
DNS 2: Server failure. The name server encountered an internal error while processing the query.
DNS 4: Not Implemented. The name server does not support the requested query type or operation.
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 4 when you sent a query type (e.g., IXFR, dynamic update) that the server does not support or has disabled.
कब किसका उपयोग करें
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 4 (NOTIMP): Verify the server supports the query type you are using. If you need zone transfers or dynamic updates, enable them in the server configuration.