why not caching?, not resolving?

[Charlie Romero]

I am in the process of setting up my own dedicated (RH6.1, BIND 
8.2.2) primary DNS. I've been testing things for a week now and 
yesterday I started noticing a problem names aren't resolving all of 
the sudden. Any clue as to why BIND all of the sudden stopped 
resolving names?

Also, Why is it that some domains seem to resolve so much quicker 
than others. before yesterday's problem started some names like Yahoo 
resolve very quickly when others take so long, Yahoo resolves quicker 
than my own local domains. Any help or suggestions appreciated.

Charlie