Configuring Windows XP as a NTP Network Time Server

Time synchronisation in modern computer networks is essential, all computers need to know the time as many applications, from sending an email to storing information are reliant on the PC knowing when the event took place.Microsoft Windows XP has a time synchronisation utility built into the operating system called Windows Time (w32time.exe) which can be configured to operate as a network time server. Windows XP can easily set the system clock to use UTC (Coordinated Universal Time, the World’s time standard) by accessing an Internet source (either: time.windows.com or time.nist.gov). To achieve this, a user merely has to double click the clock on their desktop and adjust the settings in the Internet Time tab.It must be noted however, that Microsoft and other operating system manufacturers strongly advise that external timing references should be used as Internet sources can’t be authenticated.NTP (Network Time Protocol) is a protocol already installed on Windows XP and is used by Windows Time to keep machines synchronised to the single time source. Specialist NTP servers are available that can receive a reliable time source via the GPS signal or specialist radio transmissions that get their time from atomic clocks.If you wish to configure Windows XP to operate as a time server then first thing is to locate the Windows Time subkey. To do this, run Regedit (Click start/run/then type REGEDIT/and click enter.)Note: editing your system registry can cause problems with your system. It is advisable to back up your system before editing the registry.Now locate the following subkey: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\parameters\Right click the right-hand side and click Modify. In the Edit Value box, under Value Data, type NTP and then click OK.Now go to the Config folder and right-click AnnounceFlags, Modify and in the Edit DWORD Value box, under Value Data, type 5, and then click OK.Locate this subkey:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient\Right-click in the right-side window and Modify. Edit the DWORD value box and type the number of seconds you want for each poll under Value data, i.e.: 900 will equal 15 minutes. The poll field represents the polling interval between NTP poll packets.To allow Windows XP to operate as a network time server, the NTP service needs to be switched on. To activate NTP simply find the following subkey in the registry editor (regedit):HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer\Right click enabled (in the right-hand window) then Modify. Edit the DWORD Value and type 1. Right-click NtpServer, then Modify and in the Edit DWORD Value under Value Data type Peers, then click OK.Exit the registry and start windows time service by clicking Start/Run and typing: net stop w32time && net start w32time.; Then on each computer on the network (other than the domain controller which can’t be synchronised with itself) type: W32tm/resync/rediscover.