DNS 3 NXDOMAIN vs 4 NOTIMP
Both DNS 3 (NXDOMAIN) and 4 (NOTIMP) belong to the DNS Response Codes (RCODEs) category. 3 indicates that non-Existent Domain. The queried domain name does not exist in the DNS namespace. Meanwhile, 4 means that not Implemented. The name server does not support the requested query type or operation.
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.
説明
Not Implemented. The name server does not support the requested query type or operation.
このコードが表示される場合
You sent a query type (e.g., IXFR, dynamic update) that the server does not support or has disabled.
解決方法
Verify the server supports the query type you are using. If you need zone transfers or dynamic updates, enable them in the server configuration.
主な違い
DNS 3: Non-Existent Domain. The queried domain name does not exist in the DNS namespace.
DNS 4: Not Implemented. The name server does not support the requested query type or operation.
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.
You encounter 4 when you sent a query type (e.g., IXFR, dynamic update) that the server does not support or has disabled.
どちらをいつ使うか
For 3 (NXDOMAIN): Double-check the domain spelling. If you own the domain, verify your registrar settings and ensure the nameservers are correctly delegated. 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.