The latest Microsoft Windows operating systems have a built-in time synchronisations services. Windows 2000 and later operating systems have, by default, the windows time service installed, called w32time. The time service allows a Windows network to provide synchronisation of all machines within a domain. This article describes how to configure the Windows Server 2000 and 2003 time service as a SNTP server. It also shows how to modify registry entries to configure the service to provide SNTP for synchronisation of network infrastructure.

It is important to backup the registry before modifying any entries. This allows the registry to be restored to a known good state if any problems occur.

Windows 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 server to synchronise network infrastructure such as routers, servers and other time clients.

The time service is installed by default and should be present in the systems service list. The application executable is named w32time and resides in the windows system32 directory. The applications registry settings are located at:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParameters

Windows 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.

The service will synchronise to the specified time server every 8 hours, or 3 times a day. This may not be enough to maintain accurate synchronisation. This time period can be adjusted by setting the ‘Period’ parameter to how many times a day synchronisation is required. Setting the period to 24 will activate synchronisation with once every hour. The service can also be configured to act as a SNTP 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 time service can be started or stopped from the service control applet in administrative tools. The service can also be controlled from the DOS net command:

net start w32time
net stop w32time

Windows Server 2003 has extended the original service by providing a complete implementation of the network time protocol. The service, installed by default, can synchronise to a NTP time server. Indeed, by manipulating registry settings for the service it can act as both an server and client to synchronise other network clients in the domain.

The service should be present in the systems service list. The application executable is called ‘w32time.exe’. The parameter list for w32time can be found in the registry at:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32Time

To configure a Windows 2003 machine to synchronise to an external server, edit the following registry entries:

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersType
Change the server type by specifying ‘NTP’ in the ‘Type’ registry entry.

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeConfigAnnounceFlags
Set this registry entry to 5, to indicate a reliable time source.

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeTimeProvidersNTPClientSpecialPollInterval
This 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_MACHINESYSTEMCurrentControlSetServicesW32TimeTimeProvidersNTPServerEnabled
Changing the ‘Enabled’ flag to the value 1 enables the time server.

HKEY_LOCAL_MACHINESYSTEMCurrentControlSetServicesW32TimeParametersNtpServer
This parameter is used to provide a list of IP addresses or DNS names, separated by a space, of servers that the Windows 2003 machine can synchronise to.

A number of problems can be encountered when configuring the service. The network time protocol utilises UDP over TCP/IP. Therefore the TCP/IP network infrastructure must be operational for the service to be utilised. Also, issues may arise when attempts to synchronise to an inaccurate time reference are made, or if network delays are excessive.

As well as synchronising Windows servers and workstations, the application can also be used to synchronise network hardware, such as routers, switches and hubs. Any network hardware that can synchronise using NTP can be pointed to the Windows server to achieve time synchronisation. In this way the whole network and accompanying infrastructure can be synchronised.

About the Author

Dave Evans is a technical author in the field of synchronisation systems to ensure accurate time on PC’s and computer networks. Click here, to find out more about time server solutions.

Article Source: Content for Reprint