Hi,

the Windows Time service includes both an NTP Client and an NTP Server. The NTP Server is disabled by default.

If your Windows Box should act as NTP Server config a valid time source first. Either a DCF77 (Germany) Receiver or an couple of NTP Servers which you trust.

For Germany I recommend to use the NTP Server from the “physikalisch-technische bundesanstalt”.

Lets start. Configure the Windows Time Service as NTP Client.

D:\> w32tm /config /syncfromflags:manual /update /manualpeerlist:ptbtime1.ptb.de,ptbtime2.ptb.de

Configure w32time Service to start automatically

D:\> sc config w32time start= auto
D:\> net start w32time 

Configure w32time as Server

D:\> w32tm /config /reliable:yes
D:\> w32tm /config /update
D:\> reg add HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer /v Enabled /t REG_DWORD /d 1 /f
D:\> net stop wuauserv
D:\> net start wuauserv

Open Firewall

D:\> netsh advfirewall firewall add rule name="NTP Server" dir=out protocol=udp localport=123 profile=any enable=yes action=allow
D:\> netsh advfirewall firewall add rule name="NTP Server" dir=in  protocol=udp localport=123 profile=any enable=yes action=allow

Check configuration, a section NtpServer should appear

D:\> w32tm /query /configuration
...
NtpServer (Local)
DllName: C:\Windows\system32\w32time.dll (Local)
Enabled: 1 (Local)
InputProvider: 0 (Local)
AllowNonstandardModeCombinations: 1 (Local)
...

Test it from another computer

C:\> w32tm /stripchart /computer:youtNTPServer /samples:4 /dataonly
Tracking youtNTPServer[192.168.254.1:123].
Collecting 4 samples.
The current time is 22.05.2018 22:53:55.
22:53:55  -00.0636377s
22:53:56  -00.0662772s
22:53:57  -00.0583119s
22:53:58  -00.0671685s

Michael