Zeroconfig and Multicast DNS

[Fredrik Lindberg]

Pat Lashley wrote:
>> > No, I don't think that there's any good reason to restrict mDNS service
>> > discovery to .local; when you're using some other domain on the LAN, 
>> you
>> > still want to easily do the dynamic service advertisement, even if 
>> the A
>> > records are being handled by a traditional unicast DNS server and 
>> static
>> > IP allocation.
>>
>> Well, this would cause an authority conflict if it's on by default as
>> anyone on the local network would be able to announce SD records in
>> a domain they do not have authority over.
> 
> The normal use of SD requires the ability of non-privileged users to 
> announce services on the FQDN of the host upon which they are running. 
> (Think iTunes playlist sharing.)
> 
>> Do do SD updates to an DNS zone you would need to enable dynamic updates
>> on that name server, just as the Service Discovery specifications says.
> 
> What makes you think that there even IS a unicast DNS server for the 
> (sub)domain in question?

I would expect anyone using a real domain (as in using a real TLD,
and a name registered at a domain registrar) to have a unicast DNS
server. Otherwise they have no "right" to use that name, even if
it is only in a local network.


>> I don't say that we shouldn't support it, but it should not be on by
>> default. And it will actually boil down to what the mdns nss module
>> allows.
> 
> I agree that it should not be on by default. But there should be one 
> simple knob in rc.conf to cause service advertisements to be published 
> for both .local and the host domain. Any thing more complex would 
> require editing mdns.conf.
> 

Publishing announcements is one thing, what the nss mdns module allows
a host to resolve is what will limit its initial usage.

Fredrik Lindberg