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

[Grant Edwards]

On 2012-01-21, Michael Mol <mikemol@×××××.com> wrote:
> 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,

Ah, I see.

> Thinking about it, in your device's case, I suspect you won't want
> link-local scope to be your only IPv6 address;

You're right.  We don't plan on supporting only link-local IPv6
addressing. But, I wanted to get all the basic features from the
IPv4-only version working and tested before I started worrying about
DHCPv6, router advertisements, or adding support for a user-configured
static IPv6 address.  I was surprised how difficult it was to use
link-local addresses on the development host (Gentoo) side of things.
After banging my head against the wall trying to use link-local
addresses, I've now added the capability to configure a static IPv6
address (and I set up a ULA subnet for my testing).

Now, I can use Firefox instead of curl, and I can assign the device a
hostname via Gentoo's /etc/hosts file.

> 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.

That's basically how the existing device works with IPv4 it comes with
a pre-configured static address -- however, there are Windows and
Linux management apps (that don't use IP) that the customer can use to
change that static IP address (the most common use-case) or to using
DHCP (very rare). I assume we'll update the management apps to handle
configuration of IPv6 as well.

> You could use LL addresses to bootstrap, too, but you come back to
> the browser support issue you've run into.)

Exactly.

-- 
Grant