The NTP, or Network Time Protocol, Server is aonother essential service in Linux. The need for having accurate time on Linux and other Operating Systems should be self-evident. NTP works on UDP port 123, the number for the speaking clock :) Configuration can be made via YaST or from the command line, we show you both. From the command line we edit the /etc/ntp.conf and , of course , working at the command line we are able to use diagnostic tools such as ntptrace and ntpq to help undertsand the process. The output of ntpq is show below:
The selected reference server is shown with the asterix, we can control this witht eh "prefer" option in ntp.conf. The delay, offset and jitter are all times in milliseconds. The delay is the round trip time of the packet, offset the differnce between the servera nd the reference server and the jitter shows that deviation over a period of reads bewteen the smallest and largest offset.