can we disable AAAA queries in the resolver ?

[David Malone]

On Fri, Aug 01, 2003 at 11:52:00PM -0700, Luigi Rizzo wrote:
> My understanding is that there are multiple buggy components here:
> my ISP's nameserver certainly shouldn't behave so badly on AAAA
> requests, and the applications should not bother asking AAAA queries
> when the kernel has no ipv6 support.

Usually the problem is the authorititive name server at the far
end.  Some don't reply to AAAA queries and others return NXDOMAIN
when they shouldn't. I did some measurements on hosts listed in our
cache's log and of about 24000 hosts about 200 had problems like
this.

A significant number of these are ad servers, so after complaining
to Doubleclick and getting no response, I've told my local name
server that it is authorititive for doubleclick.net and given it
an empty zone. Since doing this I don't notice the problem any more.

(Strictly speaking, you shouldn't cripple the resolver to not look
up IPv6 addresses if none are configured 'cos you might want to
look up the IPv6 address for some other reason than making a
connection.  There is a AI_ADDRCONFIG flag for getaddrinfo that
tells it to only look up addresses if you have an address in that
family configured.  For some reason it isn't mentioned in our man
page. I'm not sure what the status of our implementation is either...)

	David.