To DNS or Not To DNS…

Well…It may sound stupid but..I installed Exchange2000 in Win2k Domaincontroller and then in win2kpeofessional client i started outlook2k but i would not connect or would not accept the exchange server name when asked to give server name(when i installed exchange2000 so i gave it the name) but when i gave the ipaddress of the DC on which exchange was installed the outlook accepted it and started running perfectly. I want to still avoid giving IPadd..Wot do i have to do?..Install Internal DNS Server? or give the “hostname” of the Domain controller in outlook servername requirement box? I donno how to configure DNS internal or external with active directory and exchange2000 already there. Helllllllllllllllllllllllllllppppppppppppp!!!!!!!!