DNS 0 NOERROR vs 5 REFUSED
Both DNS 0 (NOERROR) and 5 (REFUSED) belong to the DNS Response Codes (RCODEs) category. 0 indicates that no error condition. The query completed successfully and the response contains the requested data. Meanwhile, 5 means that query refused. The name server refuses to perform the requested operation for policy reasons.
Description
No error condition. The query completed successfully and the response contains the requested data.
When You See It
This is the normal, successful response to any DNS query — the name was resolved and the answer section contains the requested records.
How to Fix
No fix needed. RCODE 0 means the DNS lookup succeeded as expected.
Description
Query refused. The name server refuses to perform the requested operation for policy reasons.
When You See It
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.
How to Fix
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.
Key Differences
DNS 0: No error condition. The query completed successfully and the response contains the requested data.
DNS 5: Query refused. The name server refuses to perform the requested operation for policy reasons.
You encounter 0 when this is the normal, successful response to any DNS query — the name was resolved and the answer section contains the requested records.
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.
When to Use Which
For 0 (NOERROR): No fix needed. RCODE 0 means the DNS lookup succeeded as expected. 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.