Before modifying registry entries it is good practice to backup the Windows registry. This allows the registry to be restored in the event of problems.
Windows 2000 ConfigurationWindows 2000 has an integrated time synchronisation service, installed by default, which can synchronise to a NTP Server. Indeed, by manipulating registry settings, the service can act as both an SNTP client and SNTP server to synchronise other network clients.
The ‘Windows Time’ service should be present in the systems service list. The application executable is ‘w32time.exe’. The parameter list for w32time can be found in the registry at:
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersWindows 2000 can operate as an NTP client and synchronise to an NTP server by setting parameter ‘NTP Server’ to the IP address of a NTP Server.
By default, the Windows 2000 machine will synchronise to the specified NTP server every 8 hours (or 3 times a day), which may not be enough to maintain accurate synchronisation. The period can be reduced by setting the ‘Period’ parameter to how many times a day synchronisation is required. Setting the period to 48 will activate synchronisation with the NTP server once every half hour.
Windows 2000 can also be configured to act as an NTP server by setting the ‘Local NTP’ parameter to ‘1’.
After editing any of the registry entries for the windows time service, the service must be restarted for the settings to take effect. The services can be started or stopped from the service control applet in ‘administrative tools’. Alternatively the service can be controlled via the DOS net command thus:net start w32timenet stop w32timeWindows 2003 ConfigurationWindows 2003 has expanded on the original Windows 2000 time service by providing a true NTP implementation. The time service, installed by default, can synchronise to a NTP Server. Indeed, by manipulating registry settings for the service it can act as both an NTP server and client to synchronise 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 w32time can be found in the registry at:
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeTo configure a Windows 2003 machine to synchronise to an external NTP server, edit the following registry entries:
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersTypeChange the server type to NTP by specifying NTP’ in the Type’ registry entry.
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeConfigAnnounceFlagsSet the Announce Flags’ registry entry to 5, to indicate a reliable time source.
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeTimeProvidersNTPClientSpecialPollIntervalThe Special Poll Interval’ registry entry defines the period in seconds that the Windows 2003 machine should poll the NTP server. A recommended value is 900 seconds, which equates to every 15 minutes.
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeTimeProvidersNTPServerEnabledChanging the Enabled’ flag to the value 1 enables the NTP Server.
HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersNtpServerThe NTP Server’ parameter is used to provide a list of IP addresses or DNS names, separated by a space, of NTP servers that the Windows 2003 machine can synchronise to.
NTP TroubleshootingA number of problems can be encountered when configuring the Windows Time Service. NTP operates using the UDP protocol over TCP/IP. Therefore the TCP/IP network infrastructure must be operational for NTP to be effective. Synchronisation issues may arise when NTP attempts to synchronise to an inaccurate time reference or if network delays are excessive.
Synchronising Network InfrastructuresAs well as synchronising Windows servers and workstations, NTP can also be used to synchronise network hardware, such as routers
, switches and hubs. Any network hardware that can synchronise to a NTP server can be pointed to the Windows server to achieve time synchronisation. In this way the whole network and accompanying infrastructure can be synchronised.