DNS 0 NOERROR vs 21 BADALG
Both DNS 0 (NOERROR) and 21 (BADALG) belong to the DNS Response Codes (RCODEs) category. 0 indicates that no error condition. The query completed successfully and the response contains the requested data. Meanwhile, 21 means that algorithm not supported. The cryptographic algorithm specified in the TKEY or SIG record is not supported by the server.
Описание
No error condition. The query completed successfully and the response contains the requested data.
Когда вы это видите
This is the normal, successful response to any DNS query — the name was resolved and the answer section contains the requested records.
Как исправить
No fix needed. RCODE 0 means the DNS lookup succeeded as expected.
Описание
Algorithm not supported. The cryptographic algorithm specified in the TKEY or SIG record is not supported by the server.
Когда вы это видите
Your TKEY negotiation or DNSSEC operation requested an algorithm (e.g., HMAC-SHA512) that the server has not been compiled with or configured to accept.
Как исправить
Use a mutually supported algorithm. HMAC-SHA256 is widely supported for TSIG; for DNSSEC, check the server's supported algorithm list with its documentation.
Ключевые различия
DNS 0: No error condition. The query completed successfully and the response contains the requested data.
DNS 21: Algorithm not supported. The cryptographic algorithm specified in the TKEY or SIG record is not supported by the server.
You encounter 0 when this is the normal, successful response to any DNS query — the name was resolved and the answer section contains the requested records.
You encounter 21 when your TKEY negotiation or DNSSEC operation requested an algorithm (e.g., HMAC-SHA512) that the server has not been compiled with or configured to accept.
Когда что использовать
For 0 (NOERROR): No fix needed. RCODE 0 means the DNS lookup succeeded as expected. For 21 (BADALG): Use a mutually supported algorithm. HMAC-SHA256 is widely supported for TSIG; for DNSSEC, check the server's supported algorithm list with its documentation.