31.2 Configuring xntp in the Network
The easiest way to use a time server in the network is to set
server parameters. For example, if a time server
called ntp.example.com is reachable from the
network, add its name to the file
/etc/ntp.conf by adding the line
server ntp.example.com.
To add more time servers, insert additional lines with the keyword server.
After initializing xntpd with the command
rcntpd start,
it takes about one hour until the time is stabilized
and the drift file for correcting the local computer clock is created.
With the drift file, the systematic error of the hardware clock
can be computed as soon as the computer is powered on.
The correction is used immediately, resulting in a
higher stability of the system time.
There are two possible ways to use the NTP mechanism as a client:
First, the client can query the time from a known server
in regular intervals. With many clients, this approach can
cause a high load on the server.
Second, the client can wait for NTP broadcasts sent out
by broadcast time servers in the network.
This approach has the disadvantage that the quality of
the server is unknown and a server sending out
wrong information can cause severe problems.
If the time is obtained via broadcast, you do not need the server name.
In this case, enter the line broadcastclient
in the configuration file /etc/ntp.conf.
To use one or more known time servers exclusively,
enter their names in the line starting with servers.