The latest Windows operating systems from Microsoft have a time synchronization service installed by default called 'Windows Time'. The time service allows a Windows network to provide time synchronization of all machines within a domain. This article introduces how to set up the Windows 2000 and Windows 2003 operating systems to operate as a NTP time server. The article describes how to modify registry entries to configure the Windows Time Service.

Before modifying any registry entries it is a good idea to backup the registry. In the even of any problems, the registry can then be restored to its former state.

Windows 2000

Windows 2000 has an integrated network time synchronization service, installed by default, which can be configured to synchronize to a Time Server. In fact, by changing associated registry settings, the service can act as both a time client and a time server to synchronize other network time clients.

The Windows Time service should be present in the systems service list. The application executable is 'w32time.exe'. The parameter list for time service should be present in the in the registry at:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParameters

The Windows 2000 operating system can operate as a time client and synchronize to a time server by setting the parameter 'NTP Server' to the IP address of a Time Server.

By default, the Windows 2000 machine will synchronize to the specified time server every 8 hours, or 3 times a day. This may not be enough to maintain accurate synchronization and can be easily increased. Setting the 'Period' parameter to how many times each day synchronization is required can reduce the period. Setting the 'Period' parameter to 48 will activate synchronization with the time server once every half hour.

The Windows 2000 operating system can also be configured to act as a time server by setting the 'Local NTP' registry setting to '1'.

After changing any of the registry settings for the windows time service, the service must be restarted for the settings to take effect. The time service can be started or stopped from the service control applet in the Administrative Tools menu. The service can also be controlled via the DOS net command using:

'net start w32time' and 'net stop w32time'

Windows 2003

With Windows 2003, Microsoft has reportedly expanded on the original Windows 2000 time service by providing a true NTP implementation. The Windows 2003 time service, installed by default, can synchronize to a NTP Server. Indeed, by changing registry settings, the time service can act as both a time server and client to synchronize other network clients in the domain.

The 'Windows Time' service should be present in the systems service list. The application executable is 'w32time.exe'. The parameter list for the Windows 2003 time service should be present in the registry at:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32Time

To configure the Windows 2003 operating system to synchronize to an external time server, edit the following registry entries:
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersType
Set the 'Type' registry entry to 'NTP', which specifies synchronization to a NTP time server.

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeTimeProvidersNTPClientSpecialPollInterval
The 'Special Poll Interval' registry entry defines the period in seconds that the Windows 2003 operating system should poll the time server. A recommended value is 900, which equates to a polling period of every 15 minutes.

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeConfigAnnounceFlags
Set the 'Announce Flags' registry entry to 5 indicating a reliable time reference.

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeTimeProvidersNTPServerEnabled
Changing the 'Enabled' flag to the value 1 enables the NTP Time Server.

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersNtpServer
The 'NTP Server' parameter is used to provide a list of DNS names or IP addresses, separated by a space, of time servers that the Windows 2003 operating system can synchronize to.

Troubleshooting

A number of problems may be encountered when setting up the Windows Time Service. Network Time Protocol operates using the UDP protocol over TCP/IP. Therefore, the TCP/IP network protocol must be operational for NTP to operate successfully. Synchronization problems may also arise when NTP attempts to synchronize to an inaccurate timing reference or if network delays are overly excessive.

Synchronizing Network Components

In addition to synchronizing Windows servers and workstations, time servers can also be used to synchronise network components, such as switches, routers and hubs. Any network components that can synchronise to a NTP time server can be pointed to the Windows server to achieve synchronization. In this way the whole network and accompanying components can be accurately synchronized.