How to Configure Windows Server as a Ntp Server

The Microsoft Windows operating systems fromsettings, the service can act as both an SNTP client
Windows 2000 onwards has a built-in timeand SNTP server to synchronise other network
synchronization service - 'Windows Time'. This articleclients.
describes how to configure the Microsoft WindowsBefore modifying registry entries it is good a dood
2003 and Windows 2000 time service as a NTP timeidea to backup the registry settings. The registry can
server. It shows how to modify registry entries tothen be restored in the event of problems being
configure the Microsoft Windows Time Service. Theencountered.
Windows Time service allows a Windows network toThe 'Windows Time' service should be present in the
provide synchronisation of all machines within asystems service list. The application executable is
domain.'w32time.exe'. The parameter list for w32time can be
Windows 2003 Server Configurationfound in the registry at:
Windows 2003 has expanded on the originalServices\W32Time\Parameters
Windows 2000 time service by providing a true NTPWindows 2000 can operate as an NTP client and
implementation. The time service, installed by default,synchronise to an NTP server by setting parameter
can synchronise to a NTP Server. Indeed, by'NTP Server' to the IP address of a NTP Server.
manipulating registry settings for the service it canBy default, the Microsoft Windows 2000 machine will
act as both an NTP server and client to synchronisesynchronise to the specified NTP time server every
other network clients in the domain.8 hours (or 3 times a day), which may not be
The 'Windows Time' service should be present in theenough to maintain accurate synchronisation. The
systems service list. The application executable isperiod can be reduced by setting the 'Period'
'w32time.exe'. The parameter list for w32time can beparameter to how many times a day synchronisation
found in the registry at:is required. Setting the period to 48 will activate
Services\W32Timesynchronisation with the NTP server once every half
Before modifying registry entries it is good a doodhour.
idea to backup the registry settings. The registry canWindows 2000 can also be configured to act as an
then be restored in the event of problems beingNTP server by setting the 'Local NTP' parameter to
encountered.'1'.
To configure a Windows 2003 machine toAfter editing any of the registry entries for the
synchronise to an external NTP server, edit thewindows time service, the service must be restarted
following registry entries:for the settings to take effect. The services can be
Services\W32Time\Config\AnnounceFlagsstarted or stopped from the service control applet in
Set the 'Announce Flags' registry entry to 5, to'administrative tools'. Alternatively the service can be
indicate a reliable time source.controlled via the DOS net command thus:net start
llIntervalw32timenet stop w32time
The 'Special Poll Interval' registry entry defines theNTP Troubleshooting
period in seconds that the Windows 2003 machineA number of problems can be encountered when
should poll the NTP server. A recommended value isconfiguring the Windows Time Service. NTP operates
900 seconds, which equates to every 15 minutes.using the UDP protocol over TCP/IP. Therefore the
Services\W32Time\Parameters\NtpServerTCP/IP network infrastructure must be operational
The 'NTP Server' parameter is used to provide a listfor NTP to be effective. Synchronisation issues may
of IP addresses or DNS names, separated by aarise when NTP attempts to synchronise to an
space, of NTP servers that the Windows 2003inaccurate time reference or if network delays are
machine can synchronise to.excessive.
Synchronising Time on Network Devices
Changing the 'Enabled' flag to the value 1 enables theAs well as synchronising Microsoft Windows servers
NTP Server.and workstations, NTP can also be used to
Services\W32Time\Parameters\Typesynchronise network devices, such as hubs, switches
Change the server type to NTP by specifying 'NTP' inand routers. Any network device that can
the 'Type' registry entry.synchronise to a NTP server can be pointed to the
Windows 2000 Time Service ConfigurationWindows server to achieve time synchronisation. In
Windows 2000 has an integrated time synchronisationthis way the whole network and accompanying
service, installed by default, which can synchronise toinfrastructure can be synchronised.
a NTP Server. Indeed, by manipulating registry