RE: v6ops-v6onbydefault: link-locals and AI_ADDRCONFIG

["Tony Hain" <alh-ietf@tndh.net>]

Pekka Savola wrote:
> ...
> IMHO, using link-local addresses for anything except well-specified
> purposes (e.g. routing protocols, RFC2461/2, etc.) is really, really
> counter-productive

in your limited world this is undoubtedly true, but there is a wider world
out there.

> -- as you'll have to make those apps be able to
> distinguish the zone identifiers as well, and that's probably
> something we
> DON'T want to do.  But your mileage may vary.
>
> So, I'll conclude by a few questions to give food for thought:
>
>  - does this seem like a  problem, that is, should getaddrinfo() +
>    AI_ADDRCONFIG perform AAAA DNS queries etc. if
>    the node only has v6 link-local/loopback addresses?

It is not a problem if you follow addr selection rules and prefer matching
scopes. This will cause IPv4 to be used if there is only a LL, trying to
talk to a AAAA global.

>
>  - is getaddrinfo() + link-local addresses something we should support?

Absolutely in the standard. In your specific network, you can turn this off
if it causes you to loose sleep at night.

>
>  - should this be fixed by e.g.:
>    a) recommending that the implementations filter out
> link-locals as well
>       when doing AI_ADDRCONFIG (a BCP/Info document)
>    b) specifying additional semantics for AI_ADDRCONFIG
>    c) specifying a new hint which would perform this
>
> Note: if we go select any of these (especially the latter two), it might
> make sense to bring this discussion up in the relevant API forums like
> POSIX as well, because the IETF API documents are just Informational RFCs.
>
> --
> Pekka Savola                 "You each name yourselves king, yet the
> Netcore Oy                    kingdom bleeds."
> Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings
>
>
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