[ILUG] making bind not ask about private subnets

[Brendan Kehoe]

My local DHCP server is on the 192.168.20.0/24 subnet; while using
tcpdump for something else, I saw this go by:

       12:33:28.627414 IP inara.network.home.40383 >
ie-dub01a-dns01.upc.ie.domain: 31110+ [1au] PTR?
24.1.168.192.in-addr.arpa. (54)

(The 192.168.1.0/24 subnet is what's used by the UPC Cisco router;
192.168.20.0/24 is maintained by a Linksys access point, to work around
speed/usability problems I found trying to use the Cisco box directly. 
But that's been talked about in other threads...)

What's the right way to configure bind to make sure it won't look
outside for anything related to 192.168.0.0/16 or 10.0.0.0/8 ?

Thanks for any suggestions,
B