DHCPv6 *still* broken for F17 alpha

Tore Anderson tore at fud.no
Fri Mar 16 19:19:50 UTC 2012

* Petr Pisar

> How does fd00::/16 differes from Why getting site scope
> address in IPv4 is Ok, while getting such address in IPv6 is considered
> as failure?

Just a little comment regarding the terminology used here. The terms
"global", "site", and "link" scope have very specific and defined
meanings in IPv6. If you run "/sbin/ip -6 address list" you will see
that all the addresses returned include their scope. You can also select
addresses by their scope (e.g. do stuff like "/sbin/ip -6 address flush
scope global").

ULAs, fd00::/7, explicitly have a global scope. This is because their
reachability is not restricted to a single organisation or site - one of
the main features of ULAs compared to site-scoped addresses are that
even though they won't be seen on the public internet, two separate
organisations can very well connect using VPNs or private interconnects
and use their own separate ULA prefixes to communicate. In other words,
the scope of ULA addresses are defined by the routing and network
topology around them, not by the actual addresses themselves. Look at
RFC 4193 for more details (in particular section 3.3).

This means that if NM's connectivity check were to report that it had
"site" connectivity when only having ULA addresses configured, it would
actually be incorrect as far as IPv6 terminology goes. It would be more
correct to say "not internet" or something along those lines.

Best regards,
Tore Anderson

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