dnstap logging based on rcode
Motivation
When FORMERR or SERVFAIL happen in the middle of resolution, we don't have exact information what we have sent and what exactly came back. We have to guess and attempt to reproduce the problem with dig
or other tools.
Request
Add parameter to dnstap
statement which would allow logging just selected RCODEs. Presumably FORMERR and/or SERVFAIL. I imagine that this could be so low-touch that it could be running in production indefinitely (as a cyclic buffer).