How to enble NTP server on Windows System to sync the time with Robustel device in a private network?

Overview

The customer's factory operates on a pure internal network. Robustel R5020Lite gateway is required to collect data and transmit it to the factory's server database (Windows Server) for storage. Simultaneously, as the database has an MQTT program enabled, time synchronization with the gateway is necessary for proper communication. The steps below show how to enable the Windows NTP service, allow UDP port 123 and point the router to the private server. In practice, private NTP works only when the Windows service, firewall and network route are all available.

What You Will Need

Hardware List:

1x Robustel R5020Lite Gateway

1x Ethernet Cable

1x Computer

Step-by-Step Configuration Guide

Step 1: Execute `services.msc`from the Run window and confirm that the Windows Time service is set to start automatically.

Step 2: Enter the Powershell interface and type in the corresponding command

w32tm /config /manualpeerlist:"127.0.0.1" /syncfromflags:manual /reliable:yes /update
Restart-Service w32Time

（Configure the clock source to local COMS time）

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\Services\w32time\TimeProviders\NtpServer" -Name "Enabled" -Value 1

（Enable the service）

Set-ItemProperty -Path "HKLM:\SYSTEM\CurrentControlSet\services\W32Time\Config" -Name "AnnounceFlags" -Value 5

（Modify to a reliable clock source）

Restart-Service w32Time

（Restart the time service to complete）

Verification and Testing

R5020Lite——PC（NTP Server:192.168.0.35）

FAQ

Q1: Why does the router fail to synchronize with a Windows NTP server?

A: Check that the Windows Time service is configured to provide NTP, UDP port 123 is allowed by the Windows firewall and the router can reach the server's IP address across the private network.

Q2: Can a Windows PC provide NTP without internet access?

A: Yes. A reachable Windows host can act as the time source inside a private network, provided its own clock is maintained correctly and the NTP service is enabled.

Q3: How can I verify successful NTP synchronization?

A: Check the router's time-status page or system log, then compare its clock with the Windows server. The configured server should be reachable and the time difference should converge after synchronization.

Conclusion

The workflow for Windows NTP server time synchronization on a private network on Robustel R5020-Lite Industrial Dual-SIM 5G Router should be considered complete only when the router reports the Windows host as its time source and its clock matches the server. This keeps logs, certificates and scheduled actions aligned in an isolated deployment.

Revision History

Version	Date	Author	Changes
1.0	2025-09-23	Tony Li	Initial documentation

Enble NTP server on Windows System to sync the time with…