Where is ntpdate

A number of samples are obtained from each of the servers specified and a subset of the NTP clock filter and selection algorithms are applied to select the best of these. Note that the accuracy and reliability of ntpdate depends on the number of servers, the number of polls each time it is run and the interval between runs. This is useful in some cases to set the clock initially before starting the NTP daemon ntpd [char46] It is also possible to run ntpdate from a cron script.

However, it is important to note that ntpdate with contrived cron scripts is no substitute for the NTP daemon, which uses sophisticated algorithms to maximize accuracy and reliability while minimizing resource use. Finally, since ntpdate does not discipline the host clock frequency as does ntpd , the accuracy using ntpdate is limited. Time adjustments are made by ntpdate in one of two ways. If ntpdate determines the clock is in error more than 0. If the error is less than 0.

Post as a guest Name. Email Required, but never shown. The Overflow Blog. Podcast The first ten years of our programming lives. Featured on Meta. Now live: A fully responsive profile. Linked 6. Related 7. Hot Network Questions. Question feed. Ask Ubuntu works best with JavaScript enabled. If the error is less than 0. The latter technique is less disruptive and more accurate when the error is small, and works quite well when ntpdate is run by cron every hour or two.

When running ntpdate on a regular basis from cron as an alternative to running a daemon, doing so once every hour or two will result in precise enough timekeeping to avoid stepping the clock. Note that in contexts where a host name is expected, a -4 qualifier preceding the host name forces DNS resolution to the IPv4 namespace, while a -6 qualifier forces DNS resolution to the IPv6 namespace.

A list of public NTP server pools for different regions is available on Internet. The ntpdate utility performed synchronization, as a result, 54 seconds were added to the local system time. If after the time synchronization with the NTP server command for example, ntpdate 0.