Zeroconfig and Multicast DNS

[Pat Lashley]

> > I would agree that LLA is part of the minimal set; and as I mentioned
> > before, it is the only part for which there is currently no FreeBSD
> > solution. It should be possible to enable LLA on a per-NIC basis in
> > rc.conf; and it should be possible to have both LLA and non-LLA addresses
> > on the same port so that a FreeBSD host can easily operate in a mixed
> > environment. (This also makes it easier for portable machines to handle
> > being moved between a zeroconf-based environment and a more traditional
> > DHCP environment.)
>
> I don't see how we can do the fallback stuff with our current
> infrastructure.  You could do it with profile.sh, but our current
> infrastructure isn't really suited to it.  In some ways what we really
> need is an all knowing IPv4 address configuration program that can probe
> the link and decide if it should a) use a static IP, b) use DHCP, or c)
> use an LLA.  It's possible we could do this in a shell script, but I'm
> not sure we'd want to.

I don't think those should necessarily be mutually exclusive.  I'd much rather 
see something that uses aliases so that I can easily have both an LLA and a 
non-LLA address on the same interface.  The only potentially tricky part is 
that the RFC requires (quite rightly) that in such a situation, the non-LLA 
address be preferred. If it were strictly a 'pick one' situation; then we could 
just extend our current setup so that the DHCP client could be told to fall 
back to LLA if it can't obtain a lease.

I suspect that it will be less common to want to use both an LL/DHCP address 
and a static address; but I certainly wouldn't rule it out. (In fact, now that 
I think about it, I'm likely to run into that situation during the transition 
of my LAN from static RFC-1918 addresses to LLA.)



-Pat