RE: ntp

["David Schwartz" <davids@webmaster.com>]

> When i start the ntp service successful on server, the client must ntpdate
> with the server after waiting a moment.
> The moment may be 3~5 minutes, or it may be 10~15 minutes. I
> don't know why
> it happens?

Two clocks cannot be synchronized instantaneously. It takes time to compare
the two clocks and adjust so that they stay in sync. A client will not
accept a date from an NTP server whose clock is not synchronized -- why
should it?

Imagine this -- you have a clock you do not trust. You ask a clock you do
trust what time it is, and it tells you it is 10:00. A bit later, I ask you
what time it is. Your clock says 10:12. Can you trust that time? Your clock
may be fast, it may be slow. You don't know. Until you check the clock you
trust a few times and confirm both clocks are flowing at the same rate, you
cannot tell the client what time it is when it asks you.

DS