Surprisingly not well documented Windows 2003 as a NTP server takes only two registry changes. It is unclear whether the first change is absolutely required. It would seem thru testing that the Windows time service W32tm can either be a Client or a server but not both. My current solution is to have another Windows server configured to receive time updates from a gov time server, My internal NTP server is configured to sync against that machine twice a day using a scheduled task that basically does a "net time \\server /set /y" avoiding the conflict.
1. Configuring the Windows Time service to use an internal hardware clock
Edit DWORD Value, type A
2. Enable NTP Server
0 The time-service provider should not be started.
1 The time-service provider should be started.