DNS 0 NOERROR vs 23 BADCOOKIE
Both DNS 0 (NOERROR) and 23 (BADCOOKIE) 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, 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
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
Bad or missing server cookie. The DNS COOKIE option in the request is absent, malformed, or does not match the server's expected value.
When You See It
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.
How to Fix
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.
Key Differences
DNS 0: No error condition. The query completed successfully and the response contains the requested data.
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 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 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.
When to Use Which
For 0 (NOERROR): No fix needed. RCODE 0 means the DNS lookup succeeded as expected. 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.