1.1. Change Windows Server 2012 network profile to Private

As default, Windows Server (R2) 2012 set its network profile to Public. Not as in Windows Server 2008 in which we can change profile via GUI, in Server 2012, we can change via Windows PowerShell (It seems that MS is forcing us to go back to command line OS)

1. Open Windows PowerShell
2. Run Set-NetConnectionProfile -NetworkCategory Private
3. Check if the profile has changed by running Get-NetConnectionProfile

1.2. Setting the server to use an NTP server

Internet time tab on the clock/date control panel was completely missing. The server joined the domain. When any computer joins a domain, the Internet Time tab is removed. This will happen for ANY version of windows. The thought was that when the client logs on, the time will be sync'ed to the domain time server.

Check it's current status first:

w32tm /query /status

It's likely that the source will be set to 'local CMOS clock'.

From an elevated position, open command prompt:

w32tm /config /syncfromflags:MANUAL /manualpeerlist:uk.pool.ntp.org
w32tm /config /update

I've used uk.pool.ntp.org but any NTP server can be added by changing the above line.

Try the status command again to see if the source has changed. If it hasn't try the following:

w32tm /resync
or
net stop w32time
net start w32time

Another command which may also work is:

w32tm /config /manualpeerlist:uk.pool.ntp.org

Don't forget to restart the service afterwards.

Further reading: https://technet.microsoft.com/en-us/windows-server-docs/identity/ad-ds/get-started/windows-time-service/windows-time-service-tools-and-settings