DNS 3 NXDOMAIN vs 5 REFUSED
Both DNS 3 (NXDOMAIN) and 5 (REFUSED) 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, 5 means that query refused. The name server refuses to perform the requested operation for policy reasons.
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
Query refused. The name server refuses to perform the requested operation for policy reasons.
このコードが表示される場合
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.
解決方法
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.
主な違い
DNS 3: Non-Existent Domain. The queried domain name does not exist in the DNS namespace.
DNS 5: Query refused. The name server refuses to perform the requested operation for policy reasons.
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 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.
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 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.