I'm primarily in a OSX environment and I'm seeing a large number of NXDOMAIN responses from our internal DNS servers. The queries that trigger these responses are what I believe to be mDNS/Bonjour style addresses that look like the following:
b._dns-sd._udp.company.com r._dns-sd._udp.0.35.16.172.in-addr.arpa b._dns-sd._udp.0.1.168.192.in-addr.arpa dr._dns-sd._udp.0.1.168.192.in-addr.arpa lb._dns-sd._udp.0.1.168.192.in-addr.arpa b._dns-sd._udp.0.1.1.10.in-addr.arpa
Each host gets around 4000 NXDOMAIN responses a day for. I don't believe this is normal for OSX machines, at least I hope not. Also, our internal DNS servers recursively request answers from these addresses to the root name servers which can't answer them.
Does anyone know how I can stop the workstations from sending these requests and/or how to tell my internal name servers (BIND 9) to not "forward" these requests to the internet? We use Bonjour internally for easy printer configuration and screen sharing.
EDIT: the requests that make it to the internet are only PTR (reverse) queries.