DNS 11 DSOTYPENI vs 16 BADVERS/BADSIG
Both DNS 11 (DSOTYPENI) and 16 (BADVERS/BADSIG) belong to the DNS Response Codes (RCODEs) category. 11 indicates that dSO-TYPE Not Implemented. The DNS Stateful Operations (DSO) type in the request is not supported by the server. 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.
Description
DSO-TYPE Not Implemented. The DNS Stateful Operations (DSO) type in the request is not supported by the server.
When You See It
Your client attempted a DSO operation (like a keepalive or push subscription) that the server does not recognize or has not implemented.
How to Fix
Verify that both client and server support the same DSO-TYPE. Upgrade the server software or fall back to traditional DNS queries.
Description
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.
When You See It
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.
How to Fix
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.
Key Differences
DNS 11: DSO-TYPE Not Implemented. The DNS Stateful Operations (DSO) type in the request is not supported by the server.
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 11 when your client attempted a DSO operation (like a keepalive or push subscription) that the server does not recognize or has not implemented.
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.
When to Use Which
For 11 (DSOTYPENI): Verify that both client and server support the same DSO-TYPE. Upgrade the server software or fall back to traditional DNS queries. 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.