DNS 5 REFUSED vs 6 YXDOMAIN
Both DNS 5 (REFUSED) and 6 (YXDOMAIN) belong to the DNS Response Codes (RCODEs) category. 5 indicates that query refused. The name server refuses to perform the requested operation for policy reasons. Meanwhile, 6 means that name Exists when it should not. Used in dynamic updates to indicate a name that should not exist already has records.
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.
Description
Name Exists when it should not. Used in dynamic updates to indicate a name that should not exist already has records.
When You See It
A DNS UPDATE prerequisite check failed because the domain name already exists when the update expected it to be absent.
How to Fix
Review your dynamic update prerequisites. If you expect to create a new name, remove the existing records first or change the prerequisite to allow existing names.
Key Differences
DNS 5: Query refused. The name server refuses to perform the requested operation for policy reasons.
DNS 6: Name Exists when it should not. Used in dynamic updates to indicate a name that should not exist already has 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.
You encounter 6 when a DNS UPDATE prerequisite check failed because the domain name already exists when the update expected it to be absent.
When to Use Which
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. For 6 (YXDOMAIN): Review your dynamic update prerequisites. If you expect to create a new name, remove the existing records first or change the prerequisite to allow existing names.