Re: Link-local connectivity in Web browsers

Hi Michael, and thanks for your review! Responses inline.
David

On Wed, Feb 21, 2024 at 5:24 AM Michael Sweet <msweet@msweet.org> wrote:

> David,
>
> I am neutral about this draft, mainly because it assumes that mDNS will
> always work


That's fair, I've added a paragraph explaining when it doesn't.


> and side-steps the very real multiple interface + mDNS issues.
>

Which issues are you referring to here?

It also is missing the IETF URI WG's first efforts (never adopted but
> historically relevant):
>
>     https://datatracker.ietf.org/doc/draft-fenner-literal-zone/


Thanks. I've incorporated the history you mentioned on the 6man list [1]
into the draft.

[1] https://mailarchive.ietf.org/arch/msg/ipv6/Pl-y5t0smD8riU9LFV3V4BdbLjU/

Finally, nothing prevents X.509 certificates from being used for mDNS
> hostnames. The issue is having a suitable trust anchor/CA, which is the
> focus of the following draft:
>
>     https://datatracker.ietf.org/doc/draft-sweet-iot-acme/


Agreed. I've clarified that this is the current state of affairs and that
future work could solve that.

WRT specific guidance about IPv6LL alternatives:
>
> 1. mDNS hostnames are generally a useful solution, with the caveat that
> the network needs to support multicast traffic and the hostnames should
> include unique identifiers such as MAC addresses to minimize the chances
> that you'd get duplicate hostnames on different interfaces. And aside from
> the multiple-interface scenario, there is also the roaming scenario to
> consider ("router.local" on different networks as you move from place to
> place).
>

Agreed. The draft did mention the need for unicity, but I've made it
stronger.

2. Locally-Unique Addresses (ULAs) can be assigned automatically and are
> better supported by the various client OS's than the RFC 4007 default scope
> for link-local addresses.
>

ULAs require some centralized addressing infrastructure to communicate the
ULA prefix to all nodes. I agree that it's a better choice when available
though.

> On Feb 20, 2024, at 11:53 PM, David Schinazi <dschinazi.ietf@gmail.com>
> wrote:
> >
> > Hi HTTP enthusiasts,
> >
> > [I'm creating a separate thread from [1] to avoid further cross-posting.]
> >
> > Some of you might have seen various discussions around the use of IPv6
> link-local addresses (such as fe80::1234%eth0) in Web browsers. In
> particular, RFC 6874 had added a way to represent these addresses in URIs.
> I wasn't involved back then but the published RFC ended up being something
> that was quite complex to implement safely in browsers, so it didn't get
> wide support. More recently, draft-ietf-6man-rfc6874bis attempted to create
> a new URI format for such addresses. Oddly, I didn't see it ever discussed
> on this list. That draft had other issues in terms of how it handled the
> Web security model, and ultimately there hasn't been consensus to publish
> it.
> >
> > I think it would be great for us to obsolete RFC 6874 and instead
> recommend a solution that already works with every browser today: mDNS. So
> I wrote a draft that does that:
> >
> >
> https://datatracker.ietf.org/doc/draft-schinazi-httpbis-link-local-uri-bcp/
> >
> > I'd love to get your thoughts on it!
> >
> > Thanks,
> > David
> >
> >
> > [1]
> https://lists.w3.org/Archives/Public/ietf-http-wg/2024JanMar/0111.html
>
> ________________________
> Michael Sweet
>
>