NPT port it is used by the Network Time Protocol for computer clock synchronization through the network by using packet switching and variable data latency.
NTP port number is 123 and it uses the UDP transport layer. Do not confuse ntp port 123 with other time related protocols like Time Protocol (port 37) and Daytime protocol (port 13).
SNTP port (Simple Network Transfer Protocol) is located on number 123 and basically it is a simpler interpretation of the ntp protocol. It is usually used on devices that don’t require high accuracy timing.
General questions about ntp port :
1. What is the ntp port number for MAC computers?
Windows NTP port , MAC , Linux are all located on the same number 123, also ntp server port is 123.
2. How to do NTP port forwarding ?
Connect to your router IP address, find the button/link called port forwarding (usually is located on the left side of your virtual router page), if the ntp port is not on the list then add id usually by clicking the “add new service” button. You will have to add service name (ntp), starting port (123), ending port (123) and server IP address.
3. How to do a ntp port check?
First change your computer time by clicking on the clock placed on your taskbar, then open command prompt window (click start, then run and in the dialog box write cmd and enter). In cmd window write net time / querysntp press enter and you will see the ntp server set on your pc. Next write in the cmd w32tm/resync, press enter and the system will update to the correct ntp server value. This is the way you test ntp port for windows machines.
4. My ntp port is block by firewall, how to unlock it?
If you have a ntp port firewall blockage all you have to do is to connect to your router and in the firewall settings add the following permissions: open port 123 for NTP and 37 for time protocol. If you have this problem on a domain you will have to open, besides 123 and 37 ports, port 9909 (Domain time 2 protocol) and 80 port. All you do is to create new ntp port firewall rules.