> On 25 Apr 2016, at 03:39, Ted Lemon <[email protected]> wrote:
> 
> On Sun, Apr 24, 2016 at 12:29 PM, Juliusz Chroboczek 
> <[email protected] <mailto:[email protected]>> 
> wrote:
> > Juliusz, the problem is that existing home network devices that do
> > DNS-based service discovery do not support DNS update. They could, but
> > they don't, because we didn't define an easy way for them to do it.
> 
> I'd be grateful if you could expand on that.  Why can't we define a way
> for clients to do DDNS?
> 
> We can and should.   The problem is that we won't see that code ship in new 
> devices anytime soon, so we still have to make mDNS work.

And this is why the dnssd WG is focused on making mDNS work on multi-subnet 
networks.

But Ted has raised the question of DNS Update there, and we agreed in BA that 
we’d accept a draft on issues around coexistence of mDNS and DNS Update.

> > Just 2136 isn't enfough, because there's no authentication scheme,
> 
> I don't understand this argument.  How is non-secured DDNS any less secure
> than mDNS?  What am I missing?
> 
> This is an implementation issue, not a security issue--sorry for not making 
> that clear.   In order to preserve the same security characteristics that 
> mDNS has, we have to ensure that the update actually originated on the local 
> link, which requires a different sort of listener than is present in a 
> typical DNS server.   And existing DNS servers typically don't have any way 
> to support unauthenticated updates on a first-come, first-served basis, so if 
> you allow unauthenticated updates, you don't have any way to avoid 
> collisions.   Otherwise you are correct.   The answer is to write a document 
> that describes how to do that, and if you read the homenet naming arch 
> document, you can see that I actually sketched out a solution there, which I 
> expect to go in a different document, likely in a different working group.

There are many worms in that can :)

> Oh, sure, we Poles are not quite as pessimistic as the Finns.  I'm
> actually of a divided mind here -- I rather like distributed solutions
> (hence prefer mDNS to DDNS) but dislike proxying.  Part of me just wishes
> we'd mandate site-local multicast and do mDNS over that
> 
> The problem with site-local multicast for mDNS is that multicast isn't a 
> great solution even on the local wire when that wire is wireless.    And, you 
> have to do modify the client anyway.

Indeed; this was discussed early on in the dnssd WG, and not considered for 
those reasons. 

> Furthermore, if you consider the mdns hybrid proxy stateless, then you can 
> have a DNS server that is roughly that stateless too.   I think it provides 
> better service continuity if you are willing to retain some state, but 
> everything will still work even if you don't, just as the hybrid proxy does.

Agreed.

Tim

> 
> _______________________________________________
> homenet mailing list
> [email protected]
> https://www.ietf.org/mailman/listinfo/homenet

_______________________________________________
homenet mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/homenet

Reply via email to