DNS 3 NXDOMAIN vs 23 BADCOOKIE
Both DNS 3 (NXDOMAIN) and 23 (BADCOOKIE) 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, 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.
Descrição
Non-Existent Domain. The queried domain name does not exist in the DNS namespace.
Quando você o vê
The domain has no DNS records at all — either it was never registered, has expired, or you have a typo in the hostname.
Como corrigir
Double-check the domain spelling. If you own the domain, verify your registrar settings and ensure the nameservers are correctly delegated.
Descrição
Bad or missing server cookie. The DNS COOKIE option in the request is absent, malformed, or does not match the server's expected value.
Quando você o vê
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.
Como corrigir
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.
Diferenças principais
DNS 3: Non-Existent Domain. The queried domain name does not exist in the DNS namespace.
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 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 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.
Quando usar qual
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 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.