DNS 1 FORMERR vs 4 NOTIMP
Both DNS 1 (FORMERR) and 4 (NOTIMP) 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, 4 means that not Implemented. The name server does not support the requested query type or operation.
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
Not Implemented. The name server does not support the requested query type or operation.
Cuándo lo verás
You sent a query type (e.g., IXFR, dynamic update) that the server does not support or has disabled.
Cómo solucionarlo
Verify the server supports the query type you are using. If you need zone transfers or dynamic updates, enable them in the server configuration.
Diferencias clave
DNS 1: Format error. The name server was unable to interpret the query due to a malformed DNS message.
DNS 4: Not Implemented. The name server does not support the requested query type or operation.
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 4 when you sent a query type (e.g., IXFR, dynamic update) that the server does not support or has disabled.
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 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.