Re: lib/42405: libc: getaddrinfo() should perform T_A lookups before T_AAAA lookups, was: Resolver problems

[Ingolf Steinbach <ingolf.steinbach%googlemail.com@localhost>]

2009/12/4 der Mouse <mouse%rodents-montreal.org@localhost>:
> How would asking for A first help?

It was *my* router which behaves strangely when confronted with AAAA
queries and which triggered the discussion. So let me sum up quickly:
- the router implements a name server
- the name server works well for A queries
- when it processes an AAAA query, it sends back the correct reply but
from a wrong source port
- the reply is ignored by the resolver (due to the unexpected source
port number)
- the resolver attempts a second AAAA query and finally falls back to
issuing an A query.
- All of this is on a box with v6 support removed from the kernel.


Please excuse my naive question: Why would the resolver want to issue
AAAA queries at all when it could (for example by investigating some
/kern setting) determine that the v6 will be useless?

Ingolf