RFC 6724

Phillip Hellewell sshock@gmail.com
Tue Nov 13 16:49:00 GMT 2018

On Tue, Nov 13, 2018 at 3:51 AM Florian Weimer <fweimer@redhat.com> wrote:
> I'm more interested in arguments for preferring some IPv4 addresses over
> IPv6 address in the destination selection algorithm, and IPv6 over IPv4
> in other cases.

In general I believe there are two goals:
1. Prefer global scope over local scope.
2. Prefer IPv6 over IPv4 (except for old/obsolete/unreliable IPv6 mechanisms).

I believe #1 takes precedence over #2, hence the reason why an IPv4
could be preferred over IPv6 in some cases.

> I'm not sure if the kernel has a concept of a home address.  That seems
> to be something that would be maintained by higher-level tools such as
> NetworkManager or systemd.

That's fine.  Then ignore rule 4 as far as getaddrinfo is concerned.
That doesn't mean throw the whole RFC out the window.  RFC 3484 had
that rule too.

All I'm asking is that the default policy table be updated; since RFC
6724 came out 6 years ago it surprises me that it hasn't already been

But at the same time I'm contracting myself because actually I don't
want the table to be updated unless we also address the concern that
local IPv6 should be preferred over local IPv4.


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