> Especially considering how rare IPv6+zones are.
Who uses IPv6+zones and why?
I'm confused what zones are about. They don't seem to be part of IPv6 packets. Where do they come from? Why does IP type have to deal with them?
Who uses IPv6+zones and why?
I'm confused what zones are about. They don't seem to be part of IPv6 packets. Where do they come from? Why does IP type have to deal with them?
It’s relatively common to encounter them in some network configurations where the routers use link-local addresses rather than global addresses in their RA packets. They are also used in SLAAC, because a device can configure a link-local address without knowing anything about its environment.
[ I think in the past there might have been an idea to use them to disambiguate site-local IPv6 addresses, but network interfaces are not sufficient in that case, and site-local addresses were problematic in lots of other ways, so they have been dropped from the specifications. ]
https://en.wikipedia.org/wiki/IPv6_address#Scoped_literal_IP...
Apparently it's possible to embed interface name into an address:
fe80::1ff:fe23:4567:890a%eth2
The article also points to an alternative solution - embed interface index into an address:
fe80:3::1ff:fe23:4567:890a
Still unclear why and where do zones come from.