Note: This page is quite old and is likely out of date. My opinions may have also changed dramatically since this was written. It is here as a reference until I get around to updating it.
There are two different means of client configuration. Fedora has a package
ntpdate that should be installed instead of ntpd. Whenever it is started
it will synchronize the server's clock to any configured time servers. It
needs to be told about time servers it should be synchronizing to in the
/etc/ntp/step-tickers. It then needs to be turned on using the following
[root@localhost ~]# chkconfig --level 345 ntpdate on
If the server doesn't have the ntpdate service (ntpdate seems like it's being deprecated though I can't imagine why) than the same thing can be accomplished by installing ntpd and adding a cron job to synchronize the time.
The following command will add a cron entry that will get run hourly and synchronize the time against the time server configured for the ntp daemon (You'll want to reference ntpd for that configuration.
echo '0 * * * * root /usr/sbin/ntpd -q -u ntp:ntp' > /etc/cron.d/ntpd
By default this file is empty and ntpdate will have no servers to get it's time from. This file should include one server per line that are either a FQDN or an IP address. If there is one or more local time servers they should be the only ones listed. If there aren't then use the following for the config file: