TABLE 1: Key Protocols in Win2K/AD Environments
Protocol	Description	UDP or TCP	Port
DNS	Name resolution services	UDP	53
LDAP	Main protocol for accessing AD information	Both	389
Kerberos	Main authentication protocol in a Win2K environment	Both	88
NTP	Provides time synchronization services	UDP	123
RPC locator	Provides port mapping services for two computers that want to communicate	TCP	135
RPC	Main protocol for interapplication communications between remote computers	TCP	>1023
Server Message Block (SMB)	Main file server protocol for accessing file shares remotely	TCP	445