Forward Unknown Lookups

[Josh Durham]

Forgive me if this has been asked before -

I'm trying to set up bind to have A records for a zone, but forward  
requests for that zone to another known server if lookups fail.

For example, on my server, I would create a record for the zone  
example.com:
server	IN	A 10.0.1.1

But I also want requests for example.com to be forwarded to another  
DNS server if mine can't resolve it.  So, in the above example, I  
would like my server to resolve 'server.example.com', but if a  
requests for another example.com name comes in, it gets forwarder.  A  
lookup for 'www.example.com' which my server would not know about  
would get forwarded.

What I'm trying to do is have some clients be able to lookup entries  
on my server (the would be using my server as their DNS server), and  
have those lookups fall through to a 'more authoritative' DNS server  
if I can't resolve it.  Sort of like a caching DNS server, but the  
server would be able to provide lookups on certain records not  
available in the forwarder server.

Thanks in advance!
- Josh