Broken DNS client resolvers (Was: Dealing with filtered 6to4 clients)

[Tore Anderson]

Hi,

* Jeroen Massar

> In short: host has IPv6 enabled, application does a getaddrinfo(), which
> means it will ask for AAAA and then A from the resolvers. The DNS
> resolver though sees a DNS query for an AAAA record and does "eeehmm
> dunno, go away" and then just drops the request. The DNS client thus has
> to time out, as that is the only option it has. The client then send a
> request for an A record and gets a direct response.

Well, this is a different problem than the one I've been describing.
I'm sure this issue is causing its share of the client loss I see on the
dualstack site too, but I believe it is smaller in scope than the
problem I've been asking about.  From what I can tell "my" problem is
responsible for more than half of the client loss on the dualstack site.

"Your" problem is incredibly hard to do anything about short of copying
Google's approach, as the problem is probably in the users' SOHO routers
most of the time and it would be impossible to contact them all and get
them to do anything about it.  Unless of course it is a common problem
with a certain type of CPE device distributed by a certain ISP, of
course, but that does not appear to be the case here.

"My" problem is confined to two specific eyeball networks here in Norway
which I think it is more likely to do be able to do something about
somehow.  If I can do that, and cut the client loss on the dualstack
site in half (now it varies between 0.12% to 0.18% from day to day) it
is more likely that my customers will be inclined to ignore the rest of
the lost clients (inluding the ones caused by "your" problem) and
proceed with dualstacking their content anyway.

By the way - the sites that have been used for the IPv6 testing have a
Norwegian reader mass (they're all in Norwegian).  So my breakage
numbers and reasons are probably very specific to Norway.

Best regards,
-- 
Tore Anderson
Redpill Linpro AS - http://www.redpill-linpro.com/
Tel: +47 21 54 41 27