DNS 5 REFUSED vs 23 BADCOOKIE
Both DNS 5 (REFUSED) and 23 (BADCOOKIE) 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, 23 means that bad or missing server cookie. The DNS COOKIE option in the request is absent, malformed, or does not match the server's expected value.
Description
Query refused. The name server refuses to perform the requested operation for policy reasons.
Quand vous le voyez
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.
Comment résoudre
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
Bad or missing server cookie. The DNS COOKIE option in the request is absent, malformed, or does not match the server's expected value.
Quand vous le voyez
Your resolver sent a query without a valid server cookie, or the cookie has expired. This is part of the DNS COOKIE mechanism to prevent spoofed-source attacks.
Comment résoudre
Retry the query — most resolvers automatically learn the correct server cookie from the first response. If the error persists, ensure your resolver supports RFC 7873 DNS Cookies.
Différences clés
DNS 5: Query refused. The name server refuses to perform the requested operation for policy reasons.
DNS 23: Bad or missing server cookie. The DNS COOKIE option in the request is absent, malformed, or does not match the server's expected value.
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 23 when your resolver sent a query without a valid server cookie, or the cookie has expired. This is part of the DNS COOKIE mechanism to prevent spoofed-source attacks.
Quand utiliser lequel
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 23 (BADCOOKIE): Retry the query — most resolvers automatically learn the correct server cookie from the first response. If the error persists, ensure your resolver supports RFC 7873 DNS Cookies.