system-config-network & Zeroconf

[Dan Williams]

On Wed, 2008-03-05 at 22:55 +0100, Lennart Poettering wrote:
> On Wed, 05.03.08 16:43, Dan Williams (dcbw at redhat.com) wrote:
> 
> > > >  Are those people...looking at using zeroconf. I get the reasoning for
> > > >  avoiding NM in a more controlled networking situation... but zeroconf
> > > >  seems like NM's bread and butter to me... but what the hell do i know.
> > > >
> > > >  -jef
> > > 
> > > 
> > > How about static IPs and multiple concurrent networks? I couldn't get
> > > either to work with network manager in F8
> > 
> > A single static IP per interface works pretty well if you use the NM in
> > updates-testing (svn3370) and have set it up to use static IP in
> > system-config-network.  Multiple IPs per interface will come eventually.
> > It'll even work before login.
> > 
> > Multiple concurrent networks are what I'm working on right now; pretty
> > good progress here and I hope to land something in the next week or so
> > in F9, and when it's pretty solid it will also show up in F8.
> 
> I haven't been following NM development lately. Just wondering: is
> there an option to explicitly select IPV4LL for configuring an IP
> address, instead of relying on dhcp-with-ipv4ll-fallback? This could

Yes, I'm thinking through that.  We do need separate booleans for DHCP
and IPv4 LL.

> be very useful for speeding up configuration in networks where most
> likely no dhcp is around, such as wlan ad-hoc, bluetooth pan, ethernet

The problem is that some people want DHCP on their WLAN adhoc
networks... I still need to figure out how the Apple connection sharing
works; they use IPv4 LL addresses in the created Ad-Hoc network but I
don't know how other machines get the default route to the one sharing
its connection.  Possibly the router announces itself with Avahi or
something.

> cross cable, usb-to-usb, ... Those ad-hoc networks are usually created

The problem with some of these, especially cable-to-cable, is that you
can't distinguish it from a situation where you do want DHCP.  Ie, you
cannot really distinguish between a crossover cable and a standard plug
into a switch.  Same with WLAN ad-hoc.

> _ad hoc_ i.e. temporarily, and thus configuration should be quick. So
> it'd be best if nm wouldn't do dhcp in these situations to avoid the
> long timeout. i.e. what I am thinking is: besides "dhcp" and "static"
> configuration for network interfaces, allow a special "zeroconf"
> configuration option. For the aforementioned ad-hoc network types
> default to "zeroconf", for the others to "dhcp" -- and then, allow
> people to switch to the other mode if they are so crazy to have a wlan
> ad-hoc network with dhcp, or a wlan infrastracture network without.

There does need to be more thought here; but I'm leaning towards
defaulting connections created when the user explicitly shares an
existing connection (ie, you pick "Share this mobile broadband card over
wireless") to zeroconf.  In the end there will still be booleans in the
config to mark DHCP yes/no and zeroconf yes/no.  I'm wondering if the
zeroconf option should be mutually exclusive with any of the others; ie
would you ever want to have a secondary IPv4 LL address at the same time
as you have a non-LL address.

Dan