1. The ntpdate client for setting system time from NTP servers. The ntpdate client allows a system's clock to be set to match the time obtained by communicating with one or more servers running the NTP protocol. The use of ntpdate is optional if you're running the ntp package, it can help a system obtain lock if it starts with a time that's pretty close by using ntpdate before starting the daemon. The ntpdate client by itself is useful for occasionally setting the time on machines that are not on the net full-time, such as laptops. From Debian 3.0r0 APT