Fwd: Re: Server issues

Sebastien Estienne sebastien.estienne at gmail.com
Wed Nov 21 01:46:44 UTC 2007


On Nov 21, 2007 1:48 AM, Scott Kitterman <ubuntu at kitterman.com> wrote:
> On Tuesday 20 November 2007 17:18, Neal McBurnett wrote:
>
> > I haven't really caught up over the last 18 months with what has
> > happened in the big IETF debates about mDNS (so-called "Apple") vs
> > LLMNR (Link-local Multicast Name Resolution - so called "Microsoft").
> >
> > But I haven't heard that there is anything on the road to
> > standardization.
> >
> > RFC 4795 was published http://tools.ietf.org/html/rfc4795
> >  Link-Local Multicast Name Resolution (LLMNR)
> >
> > but that is just an "Informational" RFC, and just about anyone who is
> > persistent enough can get one of those published.
> >
> > Security issues have been identified with both of them,
> > since they let systems mess with names that look like
> > official dns names.
> >
> > I find a lot of appeal to finding a good standard for simplified
> > configuration, like zeroconf.  But I think that it is a difficult
> > thing to get right :-(
> >
> The IESG note covers it pretty well (at least at a high level):
>
> IESG Note
>
>
>    This document was originally intended for advancement as a Proposed
>    Standard, but the IETF did not achieve consensus on the approach.
>    The document has had significant review and input.  At time of
>    publication, early versions were implemented and deployed.
>
> The lack of consensus (anyone can search the IETF main list for the last call
> discussion on this RFC, it was pretty extensive) was primarily over whether
> to use the mDNS or LLMNR protocols in the .local namespace.  Informational or
> not, it's a published RFC.  The distinction among Informational,
> Experimental, and Proposed Standard is significant within the IETF community,
> but in the wider internet world, I don't think people really know or care.

So neither is a standard, so zeroconf is not more or less 'breaking'
things than ms llmnr when using .local
And it seems that ms recommends to use .local even for unicast dns,
and thats neither a good practice.

>
> So currently we install and enable a system using an unstandarized protocol
> that works in the same namespace with another protocol that fulfills
> essentially the same purpose and that protocol is at least documented in an
> (Informational) RFC.  The key point here is that the IETF picked one and it
> isn't the one we use.

First i don't see that ietf choosed one or the other, but the real question is:
How many linux applications implement zeroconf, and how many implement llmnr?

>
> Personally, I don't like zeroconf a bit.  I like to actually configure my
> boxes before they start to talk to other boxes.

So you don't need it, that's why you can disable it.
Zeroconf is not only about setting your ip adress automatically, it's
about making your network printer just work without having to look for
an IP/PORT, it's about sharing music without asking an IP adress.

I totally agree that these technologies are only usefull in small
local network (family or small business), and should/could be disable
on servers that live in datacenters.

And that's why it's hard to have a default install for servers.
My home ubuntu server it totally different from the ubuntu servers i
run in datacenter:
- at home one server does everything from printing, dns, dhcp, lamp
- in the datacenter each farm of servers only do one task: apache,
mysql, storage, etc

that's why in the datacenter i'm using something closer to
ubuntu-minimal than the ubuntu-server CD.

And that's maybe what this thread is all about:
Having a really minimalist working install for experienced users,
personnaly i'm using FAI for my servers, it installs ubuntu-minimal +
kernel + the specific packages for the task, eg: mysql-server.

that's why i've never seen avahi on one of the servers i run in datacenters.


>
> Additionally, they are both, IMO broken by design.

How could we fix zeroconf?

>
> Scott K
>
>
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>



-- 
Sebastien Estienne




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