In my opinion the log message from system also needs to be dropped - a number of systems will use NXDOMAIN as a means of domain blocking/ad blocking, and this isn't thus an exceptional event that needs logging each time.
In my opinion the log message from system also needs to be dropped - a number of systems will use NXDOMAIN as a means of domain blocking/ad blocking, and this isn't thus an exceptional event that needs logging each time.