Zeroconfig and Multicast DNS

Pat Lashley patl+freebsd at volant.org
Fri Aug 25 03:39:34 UTC 2006


> > Except in the case where multiple interfaces are on the same segment for
> > redundancy.  But in general, I suspect that you are right that using a
> > %interface notation is the way to go.
>
> If you actually want redundancy then you don't want multiple IP
> addresses since you'll lose all your connections on the interface that
> goes down.  What you actually want is etherchannel in which case you end
> up with one IP address and one one MAC address.

Yeah, but a lot of people are going to to just figure that since their system 
came with two Ethernet ports, they should just plug them both in.  Possibly to 
two different switches; but often not even that.


> > Now, how do we handle the problem in DNS-SD ? The service records just have
> > a domain name.
>
> The resolver needs to be smart enough to resolve the domain name to the
> annotated link local address.  For the most part this probably isn't
> worth worrying about.

I'm not sure that we necessarily have enough information to do that.  I think 
we should in the simple cases using only mDNS. Bbut when you start mixing in 
the possibility of unicast DNS for service advertisement.  And the indirect PTR 
schemes that are suggested for handling things like making services with spaces 
in their names available to Windows, which doesn't accept spaces.  Then the 
possibility of different machines using the same .local FQDN, each visible on a 
different interface. And some mDNS server(s) configured to advertise services 
on behalf of non-DNS-SD-aware hosts.  I'm not sure the we're guaranteed enough 
info.

I'd be happy to find out that I'm wrong here; but I just don't have the time to 
work through all of the potential scenaria.



-Pat 


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