[ntp:questions] NTP settings for machine with irregular, short connections to the Net

Jan Ceuleers janspam.ceuleers at skynet.be
Sat Sep 8 07:52:44 UTC 2007


Rick,

Rick Jones wrote:
> If only the human scale is required, how about ntpdate run via cron or
> its platform-specific equivalent.  On the laptop, it would try to get
> time from the ISP's NTP server(s).  On the other systems it would try
> to get time from the laptop.  So, when the laptop is connected to the
> ISP network, it gets time from there and the clients simply time-out
> their ntpdate commands.  Then when it is on the little network, the
> laptop's attempt at ntpdate is the one that times-out and the clients
> get time from the laptop.

A few more points need to be made in order to make this work.

The laptop needs to run ntpd while it serves time to the other LAN 
clients. For ntpd to convince itself that it is capable of serving time 
while not connected to the ISP, it needs permission to "synchronise to" 
its own local clock.

Given that the OP won't want to change the configuration of his laptop 
each time he moves between the ISP and the LAN, he in fact won't be able 
to use ntpdate to synchronise the laptop to the ISP (because ntpd will 
be running), and instead will have to use ntpd itself for the purpose of 
synchronising the laptop to the ISP.

Cheers, Jan




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