[RT#43428] Silence some 'expected' logging messages
The user is a high volume hosting provider.
Under attack scenarios, the amount of logging BIND is doing can make a difference.
This user would like to be able to silence some sorts of frequently-recurring messages that are 'expected', because they are basically probing behavior from prospective attackers. An example would be an unsuccessful AXFR from a client that is not permitted to AXFR.
things that would ideally be logged at a higher level:
- Successful AXFR
- Terminated AXFR
- Unsuccessful AXFR from an authorized client