Bug#400390: [pkg-ntp-maintainers] Bug#400390: Please have ntp installed by default in the standard task

[Kurt Roeckx]

On Mon, Nov 27, 2006 at 09:50:31PM +0100, Olaf van der Spek wrote:
> >an ntp server, and not to run on a desktop system or something that
> >doesn't have a static IP address.
> 
> Why does it require a static IP address?

It basicly comes down to ntpd currently not supporting changing IP
addresses.  This is a very longstanding upstream bug, and I don't think
upstream really is looking into fixing this.

The NTP protocol uses UDP.  If a client sends a packet to a server,
it expects to get a response from the same IP address back.  This
creates problems for systems with multiple IP addresses.  Since there
is no API to get the IP address a packet was send to, it binds to every
IP address it finds when starting (and to the wildcard address).  So
depending on the socket, it knows which address it was send too.

I don't know exactly where the problem is, but after an IP address
change, packets start to come in at the wildcard socket, and at that
point things probably stop working.

See for instance also #399905.

> >What you might want as a default installation is an sntp client.
> 
> In that case, shouldn't the Gnome clock panel also enable/disable sntp 
> instead of ntp then?

I have no idea what the gnome clock panel can or can't do.  Taking a
quick look at it, it seems it can synchronize the clock using the 
internet, but I'm guessing it's editing my ntp.conf or something?


Kurt