Configure NTP server

If you want to exactly synchronize the date & time of multiple devices without having neither Internet connexion nor a software that make one of your devices acting as an NTP server, you can easily make any Cisco Switch or Router, or any Windows computer as NTP server.

  • CISCO Device:

Step 1: ensure that your Cisco device have date and time correctly configured, using show clock:

R1# show clock 
*20:30:05.818 UTC Sat Oct 12 2015

Step 2: set the time and date to their correct values if required:

R1# clock set 22:35:00 Feb 2 2019

Step 3: make your device acting as NTP server:

R1(config)# ntp master

  • Windows Computer:

Step 1: Stop the “Windows Time” service via Start > Control Panel > System and Security >Administrative Tools > Services.

Step 2: Open the registry editor via “Start > Run> regedit”.

Step 3: Search for the code “HKEY_LOCAL_MACHINE\SYSTEM\ CurrentControlSet\ services\W32Time\TimeProviders\NtpServer”.

Step 4: Set the “Enable” value to 1.

Step 5: Search for the code “HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ services \W32Time\Config”.

Step 6: Set the “AnnounceFlags” value to 5.

Step 7: Start the “Windows Time” again and set the start type to “Automatic”.


  • If the firewall is enabled, you must permit access to both TCP/UDP Port# 123.
  • It is highly recommended to secure NTP by configuring authentication and ACL…

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