[IPv6]Re: [v6ops] New draft: "The IPv6 Loopback Address Prefix"

[Michael Sweet <[e-mail]>]

Ole,

> On Nov 26, 2025, at 12:52 PM, Mark Smith <[e-mail]> wrote:
> 
> Hi Ole,
> 
> On Thu, 27 Nov 2025 at 00:18, Ole Trøan <[e-mail]> wrote:
>> 
>> Mark,
>> 
>> Since the loopback address is of link-local scope you can already do this with multiple loopback interfaces.
>> ::1%loop0
>> ::1%loop1
>> 
> 
> That's interesting.
> 
> One thing I think worth avoiding is having to use loopback addresses
> with zone IDs to minimise the amount of typing since these addresses
> may be commonly typed in manually.

One other thing, and something that has been a sore spot for IoT devices like printers forever, is that relying on using zone/scope IDs doesn't work for services that use URIs.  The old URI WG and somewhat more recently 6man have tried extending URIs to support IPv6 addresses with zone/scope IDs three different ways (mainly for link-local addresses but really for any address whose routing depends on it) and have failed.

There isn't a lot we can do for link-local addresses (there we have to rely on mDNS hostnames), but for loopback addresses things *should* Just Work if every loopback interface has a unique address and not "::1%ZONEID".

________________________
Michael Sweet