Zeroconfig and Multicast DNS

[Fredrik Lindberg]

Pat Lashley wrote:
>> Um..wouldn't the routing code handle this?
>> If you set a lla address and some other address on a interface like 
> 192.168.0.2
>> or something and then a default route of 192.168.0.1, I
>> would assume that an application without specific knowledge that tries
>> to contact an external address would get 192.168.0.2 as the source
>> address and that the packet is sent to 192.168.0.1.
> 
> It should handle it; but I'd still want someone to check out various 
> edge conditions and pathological cases.
> 
>> If you're in the situation that you need lla (no dhcp server available),
> 
> The presence or absence of a DHCP server is not a good indicator of the 
> need or desire for LLA and/or mDNS. It is quite possible that the system 
> is in a mixed environment where there are some systems which are 
> LLA/mDNS only, others which are DHCP/static/unicast DNS only, and others 
> which handle both.
> 
>

I treat LLA and mDNS as separate things. They can be used individually
or together. I see LLA as a way of configuring an IP-address while
mDNS is a way of resolving DNS-like hostnames.


Howevery, your statement above brings up a question, do you assume
that a system configured with lla should be able to communicate
with a system configured via dhcp?
I would assume no, per standard IP/routing rules as they would be
in different subnets and would require a router to tell them
about each other which somehow violates the link local scope of
the 169.254/16 address space.


>> you wouldn't know the default route right?
> 
> I believe that there is a way to announce routing service via mDNS-SD; 
> but I don't know the details. (I would be astonished to discover that 
> the people who developed the zeroconfig design left that bit out...)
> 

Yes, discovering a NAT-router via SD is certainly possible, but I'm not
sure if this should be in the lla-daemon or in a separate program.

Fredrik Lindberg