DNS 2 SERVFAIL vs 19 BADMODE
Both DNS 2 (SERVFAIL) and 19 (BADMODE) 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, 19 means that bad TKEY Mode. The TKEY mode field contains a value not supported by the server.
説明
Server failure. The name server encountered an internal error while processing the query.
このコードが表示される場合
The recursive resolver could not get an authoritative answer — commonly caused by DNSSEC validation failures, unreachable upstream nameservers, or misconfigured zones.
解決方法
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.
説明
Bad TKEY Mode. The TKEY mode field contains a value not supported by the server.
このコードが表示される場合
Your client attempted a TKEY key exchange using a mode (e.g., Diffie-Hellman, GSS-API) that the server does not support or has not been configured for.
解決方法
Check which TKEY modes the server supports and configure your client to use a compatible mode. GSS-TSIG (mode 3) is the most widely deployed.
主な違い
DNS 2: Server failure. The name server encountered an internal error while processing the query.
DNS 19: Bad TKEY Mode. The TKEY mode field contains a value not supported by the server.
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 19 when your client attempted a TKEY key exchange using a mode (e.g., Diffie-Hellman, GSS-API) that the server does not support or has not been configured for.
どちらをいつ使うか
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 19 (BADMODE): Check which TKEY modes the server supports and configure your client to use a compatible mode. GSS-TSIG (mode 3) is the most widely deployed.