Re: [gentoo-user] Re: Link-local ipv6 address in /etc/hosts? in browsers?

[Michael Mol]

On Fri, Jan 20, 2012 at 9:03 AM, Grant Edwards
<grant.b.edwards@×××××.com> wrote:
> On 2012-01-19, Michael Mol <mikemol@×××××.com> wrote:
>
>>>> Do you really want that much broadcast and wide multicast (think
>>>> DNS-SD and NTP in multicast mode) traffic on the same Ethernet
>>>> segment?
>>>
>>> That bit I don't understand. ??It's no worse that ARP, and we seem to
>>> live with that quite easily.
>>
>> Not just arp, but actual broadcast/multicast data. If you've ever run
>> PulseAudio and enabled network sources and sinks on a couple boxes,
>> you might have accidentally discovered an easy way to bring a wireless
>> network to its knees. And that's just something I've had personal
>> experience with. Come to think of it, that's a good reason I should
>> continue to keep my home wired and wireless networks on separate
>> subnets, and not simply bridged as I'd done at the time.
>
> I don't understand what that has to do with L-L address support in
> applications.

The "Do you really want that much broadcast and wide multicast traffic
on the same Ethernet segment" was in the context of having a large
network not divided up into separate subnets, which was in the context
of how broadcast and multicast traffic can saturate a link scope if
the link scope is too large. It was an argument against huge link
scopes, not against link-local support.

Thinking about it, in your device's case, I suspect you won't want
link-local scope to be your only IPv6 address; you'll want either a
ULA address or a global-scope address. Otherwise, clients not on the
local Ethernet segment won't be able to communicate with it, period;
the user of your device would need a proxy sitting on the segment.

Something you might think about: Register a ULA subnet, and configure
your devices to use it. That would allow the network operators at
destination sites to include network routing as a means to
restrict/allow access to it. You'll also want to allow configuration
of global-scope addresses via RAs and DHCPv6. (Though
enabling/disabling that on initial device setup will be interesting;
Having a ULA address preconfigured when you ship would be much like
one's SOHO router being preconfigured with '192.168.0.220" on its
internal interface. You could use LL addresses to bootstrap, too, but
you come back to the browser support issue you've run into.)

-- 
:wq