DNS 7 YXRRSET vs 23 BADCOOKIE
Both DNS 7 (YXRRSET) and 23 (BADCOOKIE) belong to the DNS Response Codes (RCODEs) category. 7 indicates that rR Set Exists when it should not. A resource record set exists that the update prerequisite says should not. 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.
描述
RR Set Exists when it should not. A resource record set exists that the update prerequisite says should not.
何时出现
A DNS UPDATE failed because a specific RRset (e.g., an A record) already exists when the prerequisite required it to be absent.
如何修复
Delete the conflicting RRset before retrying the update, or adjust your prerequisite conditions to match the actual zone state.
描述
Bad or missing server cookie. The DNS COOKIE option in the request is absent, malformed, or does not match the server's expected value.
何时出现
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.
如何修复
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.
主要区别
DNS 7: RR Set Exists when it should not. A resource record set exists that the update prerequisite says should not.
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 7 when a DNS UPDATE failed because a specific RRset (e.g., an A record) already exists when the prerequisite required it to be absent.
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.
何时使用哪个
For 7 (YXRRSET): Delete the conflicting RRset before retrying the update, or adjust your prerequisite conditions to match the actual zone state. 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.