
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”.
Notes:
- 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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