DNS 2 SERVFAIL vs 20 BADNAME
Both DNS 2 (SERVFAIL) and 20 (BADNAME) 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, 20 means that duplicate key name. The key name in a TKEY negotiation is already in use or conflicts with an existing key.
Descrição
Server failure. The name server encountered an internal error while processing the query.
Quando você o vê
The recursive resolver could not get an authoritative answer — commonly caused by DNSSEC validation failures, unreachable upstream nameservers, or misconfigured zones.
Como corrigir
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.
Descrição
Duplicate key name. The key name in a TKEY negotiation is already in use or conflicts with an existing key.
Quando você o vê
A TKEY key establishment failed because a key with the same name already exists on the server from a previous session that was not properly cleaned up.
Como corrigir
Use a unique key name for each TKEY session (e.g., append a timestamp or random suffix). Delete stale keys on the server if they are no longer needed.
Diferenças principais
DNS 2: Server failure. The name server encountered an internal error while processing the query.
DNS 20: Duplicate key name. The key name in a TKEY negotiation is already in use or conflicts with an existing key.
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 20 when a TKEY key establishment failed because a key with the same name already exists on the server from a previous session that was not properly cleaned up.
Quando usar qual
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 20 (BADNAME): Use a unique key name for each TKEY session (e.g., append a timestamp or random suffix). Delete stale keys on the server if they are no longer needed.