On Tue, 29 Jun 2004, Glen Johnson wrote:

> Dear netbsd-help,
> I have a small home network with a 486 as my NetBSD box.  I am in the
> process of making it do more for me.  One of the things I want to do with
> it is have it run as my time server that all my other computers synchronize
> from.  I read through most of the ntpd man page and the ntpdate man
> page.  I do understand that it is a bad idea to run them both
> simultaneously.  The man pages do a fine job of describing every possible
> flag or setting available.  What I can't find is something that pulls it
> all together to tell me what I need to do to have my 486 operate as a time
> server and yet when I dial up my ISP then sync to a  real time server, or
> three.
> Should I:
> 1.  Run ntpd when I am not connected to my ISP.
> 2. Disable ntpd before connecting to my ISP.
> 3. Run ntpdate.
> 4. R enable ntpd after the update.
>
> OR is there some special line up of flags and such that tells ntpd to do
> such a thing when I connect.  I suppose I would put such a thing in my
> ip-up script.

Could you describe your setup in a little more detail? What platform
are the other computers running? Are you NAT'ing a single dynamic IP,
is "pppd" dialing on demand, or what?

For the "dial-on-demand" NAT thing, one possibility is to make one of
the internal hosts the master running "ntpd". It'll never know about
the address changes. You can use the "active-filter-out" option to
"pppd" to keep the NTP exchange from bringing the link up, OR the
"active-filter-in" option to keep it from keeping the link up, OR not:
if you set the value to "idle" short enough -- below 17 minutes --,
it'll let the link die only once "ntpd" is feeling synced.

Frederick