Re: Link-local connectivity in Web browsers

On Wed, Feb 21, 2024 at 08:24:20AM -0500, Michael Sweet wrote:
> 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).

Inclusion of human unfriendly elements like MAC addresses is not desirable when we
are talking about use in places where 'normal users' are supposed to enter them.
In m2m communications this is supposedly widely used though.

> 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.

I am not aware of schemes that would automatically assign ULAs, would love a reference.
I have written a scheme based on network wide configuration/autoprovisioning (RFC8994), but
i am not aware of any similar solutions like that widely used.

I would say au contraire: Once you've exhausted the mDNS option, you'll probably exhaust
a lot of the IPv6 link-local address cases if you just make the alredy implemented in
browser [<IPv6address>] without zone_id option work for the default zone:

- recognize that <IPv6address> is link-local in the browsers socket interface
- determine default interface
  (something like: defzone=`netstat -r -f inet6 -n | grep default | head -1 | awk '{print $4}'`)
- attach %<defzone> to the <IPv6address> for the socket connect()
  (noewhere else needed - just because kernels have not implemented default zone)

Cheers
   toerless

> > 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
> 

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tte@cs.fau.de

Received on Thursday, 22 February 2024 01:43:27 UTC