DNS 2 SERVFAIL vs 5 REFUSED
Both DNS 2 (SERVFAIL) and 5 (REFUSED) 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, 5 means that query refused. The name server refuses to perform the requested operation for policy reasons.
Descripción
Server failure. The name server encountered an internal error while processing the query.
Cuándo lo verás
The recursive resolver could not get an authoritative answer — commonly caused by DNSSEC validation failures, unreachable upstream nameservers, or misconfigured zones.
Cómo solucionarlo
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.
Descripción
Query refused. The name server refuses to perform the requested operation for policy reasons.
Cuándo lo verás
The server rejected your query due to access control — for example, a recursive resolver that only serves its own network, or a zone transfer blocked by ACL.
Cómo solucionarlo
Check the server's allow-query, allow-recursion, or allow-transfer ACLs. If you are not authorized to use this resolver, switch to a public DNS service.
Diferencias clave
DNS 2: Server failure. The name server encountered an internal error while processing the query.
DNS 5: Query refused. The name server refuses to perform the requested operation for policy reasons.
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 5 when the server rejected your query due to access control — for example, a recursive resolver that only serves its own network, or a zone transfer blocked by ACL.
Cuándo usar cada uno
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 5 (REFUSED): Check the server's allow-query, allow-recursion, or allow-transfer ACLs. If you are not authorized to use this resolver, switch to a public DNS service.