DNS 4 NOTIMP vs 16 BADVERS/BADSIG
Both DNS 4 (NOTIMP) and 16 (BADVERS/BADSIG) belong to the DNS Response Codes (RCODEs) category. 4 indicates that not Implemented. The name server does not support the requested query type or operation. Meanwhile, 16 means that bad OPT Version or TSIG Signature Failure. Either the EDNS version in the OPT record is not supported, or the TSIG signature on the message failed verification.
الوصف
Not Implemented. The name server does not support the requested query type or operation.
متى تراه
You sent a query type (e.g., IXFR, dynamic update) that the server does not support or has disabled.
كيفية الإصلاح
Verify the server supports the query type you are using. If you need zone transfers or dynamic updates, enable them in the server configuration.
الوصف
Bad OPT Version or TSIG Signature Failure. Either the EDNS version in the OPT record is not supported, or the TSIG signature on the message failed verification.
متى تراه
As BADVERS: your client sent an EDNS version higher than the server supports. As BADSIG: the TSIG MAC on the message did not match, indicating a shared-secret mismatch or message tampering.
كيفية الإصلاح
For BADVERS, downgrade the EDNS version (most servers support version 0 only). For BADSIG, regenerate and re-synchronize the TSIG shared secret on both endpoints.
الفروق الرئيسية
DNS 4: Not Implemented. The name server does not support the requested query type or operation.
DNS 16: Bad OPT Version or TSIG Signature Failure. Either the EDNS version in the OPT record is not supported, or the TSIG signature on the message failed verification.
You encounter 4 when you sent a query type (e.g., IXFR, dynamic update) that the server does not support or has disabled.
You encounter 16 when as BADVERS: your client sent an EDNS version higher than the server supports. As BADSIG: the TSIG MAC on the message did not match, indicating a shared-secret mismatch or message tampering.
متى تستخدم أيًا منهما
For 4 (NOTIMP): Verify the server supports the query type you are using. If you need zone transfers or dynamic updates, enable them in the server configuration. For 16 (BADVERS/BADSIG): For BADVERS, downgrade the EDNS version (most servers support version 0 only). For BADSIG, regenerate and re-synchronize the TSIG shared secret on both endpoints.