Re: DNS-SD, mDNS and dyn-DNS [was Re: Gnome VFS - plans for Gnome 2.8]

[Sean Middleditch <elanthis awesomeplay com>]

On Mar 27, 2004, at 4:39 AM, Mark McLoughlin wrote:
> 	Another possible mechanism for making remote desktop service
> information available via DNS is to use Dynamic DNS Updates[20] to add
> DNS-SD records to a conventional DNS server. However, the majority of
> DNS server deployments restrict (for obvious security reasons) the
> ability to update DNS records completely or to only a few known
> hosts. Because using this mechanism would require installation sites
> to change their DNS administration policies, this is obviously not an
> attractive option.

To be honest, it's a lot better to just enable (and configure) dyn-dns 
than it is to learn, install, configure, and administrator an all new 
platform (SLP).  Large installations would already have the DNS 
fail-over set up (I know we do at my organization) and so on.  It makes 
a hell of a lot more sense to use dyn-dns than it does to install SLP.

Second, it is true that dyn-dns would limit which hosts can 
post/publish services.  That's a *good* thing.  We don't want someone 
to come in, plug in a laptop, publish an http service with a similar 
name as the company Intranet, and start stealing passphrases and such 
when users attempt to login to this rogue service.  We *want* to be 
able to limit and control who can publish what.  In fact, in a large 
organization, I would *expect* a responsible administrator to disable 
mDNS and rely solely on a well controlled central set of DNS servers.

Yes, SLP allows all of that, but then it requires new infrastructure to 
be in place.  Plus it isn't *also* capable of handling no-administrator 
ad-hoc networks like Zeroconf (mDNS + DNS-SD + IP Autoconfiguration) is 
designed to be able to handle.

Leveraging existing infrastructure to a very large degree and being 
comprised of several small inter-dependent pieces makes Zeroconf one of 
the most UNIX-y network service protocols around.  Simply amazing 
engineering.  :)