Time Synchronization using Extended Network Time Protocol (xntp)

Novell Cool Solutions: Trench
By R Mohamed Razikh Ulla

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Posted: 26 Jul 2005

Applies To:

Novell Linux Desktop 9
SUSE Linux Professional 9.3
SUSE Linux Enterprise Server 9
Open Enterprise Server

Solution:

Note: Synchronizing clock of all the computers in the network is one of most important requirement of any process flow. Computers have built-in clock to address this issue, but this clock does not meet the requirements of some critical environments such as distributed networks and testing networks. This issue can be solved by using xntp which continuously monitors and maintains the local clock by comparing local time with statistically gathered data from universal time servers. It also corrects local time by continuously querying specified time servers. By default xntp is configured to refer local computer clock to update time.

Editors Note: The procedure outlined below is also configurable though YaST by going to Yast2 | Network Services | NTP Client.

In order to access a time server on the network, the time sever needs to be specified for server parameter of xntp configuration file. For example, if the time server available is time.abc.net, then this can be declared in /etc/ntp.conf in the following format:

server time.abc.net
Similarly additional servers can be specified.
You can start the xntp daemon by executing following command:

rcxntp start
The xntp daemon waits for next 1 hour until it creates a drift file to correct local computer clock. So every time the system boots, the hardware clock will be set to accurate time by referring this drift file as it specifies the amount of time the hardware clock will off over time. In this way it maintains stable computer time. Any machine running with xntp can be made as reference to other machines in the network by enabling broadcast client option in the /etc/ntp.conf file.
A command ntpdate can also be used to synchronize computer clock with the global clock as following:

ntpdate time.nist.gov