DNS 2 SERVFAIL vs 6 YXDOMAIN
Both DNS 2 (SERVFAIL) and 6 (YXDOMAIN) belong to the DNS Response Codes (RCODEs) category. 2 indicates that server failure. The name server encountered an internal error while processing the query. 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.
Mô tả
Server failure. The name server encountered an internal error while processing the query.
Khi bạn thấy mã này
The recursive resolver could not get an authoritative answer — commonly caused by DNSSEC validation failures, unreachable upstream nameservers, or misconfigured zones.
Cách khắc phục
Try a different resolver (e.g., 8.8.8.8 or 1.1.1.1) to isolate the issue. If you control the zone, check DNSSEC signatures, SOA serial consistency, and nameserver reachability.
Mô tả
Name Exists when it should not. Used in dynamic updates to indicate a name that should not exist already has records.
Khi bạn thấy mã này
A DNS UPDATE prerequisite check failed because the domain name already exists when the update expected it to be absent.
Cách khắc phục
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.
Sự khác biệt chính
DNS 2: Server failure. The name server encountered an internal error while processing the query.
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 2 when the recursive resolver could not get an authoritative answer — commonly caused by DNSSEC validation failures, unreachable upstream nameservers, or misconfigured zones.
You encounter 6 when a DNS UPDATE prerequisite check failed because the domain name already exists when the update expected it to be absent.
Khi nào dùng cái nào
For 2 (SERVFAIL): Try a different resolver (e.g., 8.8.8.8 or 1.1.1.1) to isolate the issue. If you control the zone, check DNSSEC signatures, SOA serial consistency, and nameserver reachability. 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.