DNS 8 NXRRSET vs 16 BADVERS/BADSIG
Both DNS 8 (NXRRSET) and 16 (BADVERS/BADSIG) belong to the DNS Response Codes (RCODEs) category. 8 indicates that rR Set that should exist does not. A required resource record set is missing from the zone. 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.
Descripción
RR Set that should exist does not. A required resource record set is missing from the zone.
Cuándo lo verás
A DNS UPDATE prerequisite expected a certain RRset to exist (e.g., an MX record), but the zone does not contain it.
Cómo solucionarlo
Create the missing RRset in the zone before retrying the update, or change the prerequisite to not require its existence.
Descripción
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.
Cuándo lo verás
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.
Cómo solucionarlo
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.
Diferencias clave
DNS 8: RR Set that should exist does not. A required resource record set is missing from the zone.
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 8 when a DNS UPDATE prerequisite expected a certain RRset to exist (e.g., an MX record), but the zone does not contain it.
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.
Cuándo usar cada uno
For 8 (NXRRSET): Create the missing RRset in the zone before retrying the update, or change the prerequisite to not require its existence. 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.