When an XP Professional system is part of a domain environment, it will automatically synchronize its time with a domain controller running Windows 2000 or Windows Server 2003. In these environments, it is critical that the clocks on the domain controller and XP system have no more than a 5-minute variance, or logon will fail. For the sake of accuracy, configure the domain controller to use an external SNTP server, while leaving XP systems without SNTP settings configured.
