nslookup can't but browser can !

[Prashant Ranade]

I have a domain name server for a company say abc.com on NT machine
resolving internal machines is no problem.. but when I try to resolv
internet names I can't (using nslookup)
however if I try to go through the browser I can get to any site on the
internet even if that site is not there in the DNS cache.
can somebody pl explain this ????????

TIA
Prashant