Enables Windows Server to server NTP to clients on a network and configures the upstream time server to time.windows.com. Also creates a firewall rule to allows incoming connections to UDP port 123 for NTP clients.

Configure-NTPServer.ps1

Set-TimeZone -Name 'Eastern Standard Time'
Set-Service -Name W32Time -StartupType Automatic
Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpServer' -Name 'Enabled' -Value 1 -Force
Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\Config' -Name 'AnnounceFlags' -Value 0xA -Force
Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient' -Name 'Enabled' -Value 1 -Force
Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient' -Name 'SpecialPollInterval' -Value 300 -Force
Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\Parameters' -Name 'Type' -Value 'NTP' -Force
Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\Parameters' -Name 'NtpServer' -Value 'time.windows.com,0x8' -Force
Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\Config' -Name 'MaxPosPhaseCorrection' -Value 1800 -Force
Set-ItemProperty -Path 'HKLM:\SYSTEM\CurrentControlSet\Services\W32Time\Config' -Name 'MaxNegPhaseCorrection' -Value 1800 -Force
New-NetFirewallRule `
  -Name "NTP Server Port" `
  -DisplayName "NTP Server Port" `
  -Description 'Allow NTP Server Port' `
  -Profile Any `
  -Direction Inbound `
  -Action Allow `
  -Protocol UDP `
  -Program Any `
  -LocalAddress Any `
  -LocalPort 123
Restart-Service -Name W32Time -Force