(Adapted from: https://help.ubuntu.com)
Network Time Protocol (NTP) is a networking protocol for time and date synchronisation between computers. NTP is a TCP/IP protocol for synchronising time over a network. Basically a client requests the current time from a server, and uses it to set its own clock.
Behind this simple description, there is a lot of complexity - there are tiers of NTP servers, with the tier one NTP servers connected to atomic clocks, and tier two and three servers spreading the load of actually handling requests across the Internet. Also the client software is a lot more complex than you might think - it has to factor out communication delays, and adjust the time in a way that does not upset all the other processes that run on the server. But luckily all that complexity is hidden from you!
First, disable the ntpdate service:
sudo update-rc.d -f ntpdate remove
Install NTP:
sudo apt-get install ntp
Open and edit the ntp configuration file:
sudo nano /etc/ntp.conf
Comment out those pool servers and specifiy SP’s NTP server address:
server 172.16.110.2
Now, restart the ntp service:
sudo service ntp restart
Install NTP:
sudo apt-get install ntp
And then edit the configuration file /etc/ntp.conf:
sudo nano /etc/ntp.conf
Finally specify our NTP server address:
server 10.1.1.2
Now, restart the ntp service:
sudo service ntp restart