DNS 1 FORMERR vs 3 NXDOMAIN
Both DNS 1 (FORMERR) and 3 (NXDOMAIN) 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, 3 means that non-Existent Domain. The queried domain name does not exist in the DNS namespace.
説明
Format error. The name server was unable to interpret the query due to a malformed DNS message.
このコードが表示される場合
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.
解決方法
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.
説明
Non-Existent Domain. The queried domain name does not exist in the DNS namespace.
このコードが表示される場合
The domain has no DNS records at all — either it was never registered, has expired, or you have a typo in the hostname.
解決方法
Double-check the domain spelling. If you own the domain, verify your registrar settings and ensure the nameservers are correctly delegated.
主な違い
DNS 1: Format error. The name server was unable to interpret the query due to a malformed DNS message.
DNS 3: Non-Existent Domain. The queried domain name does not exist in the DNS namespace.
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 3 when the domain has no DNS records at all — either it was never registered, has expired, or you have a typo in the hostname.
どちらをいつ使うか
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 3 (NXDOMAIN): Double-check the domain spelling. If you own the domain, verify your registrar settings and ensure the nameservers are correctly delegated.