DNS 1 FORMERR vs 2 SERVFAIL
Both DNS 1 (FORMERR) and 2 (SERVFAIL) belong to the DNS Response Codes (RCODEs) category. 1 indicates that format error. The name server was unable to interpret the query due to a malformed DNS message. Meanwhile, 2 means that server failure. The name server encountered an internal error while processing the query.
Descripción
Format error. The name server was unable to interpret the query due to a malformed DNS message.
Cuándo lo verás
Your DNS client or library sent a query the server could not parse, often caused by a buggy resolver, corrupted packet, or unsupported EDNS options.
Cómo solucionarlo
Check your DNS client or library version for known bugs. Capture the raw query with dig or Wireshark and verify it conforms to the DNS wire format.
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.
Diferencias clave
DNS 1: Format error. The name server was unable to interpret the query due to a malformed DNS message.
DNS 2: Server failure. The name server encountered an internal error while processing the query.
You encounter 1 when your DNS client or library sent a query the server could not parse, often caused by a buggy resolver, corrupted packet, or unsupported EDNS options.
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.
Cuándo usar cada uno
For 1 (FORMERR): Check your DNS client or library version for known bugs. Capture the raw query with dig or Wireshark and verify it conforms to the DNS wire format. 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.