On Tue, Mar 22, 2005 at 09:05:39AM +0100, Ed Kapitein wrote:
> Hi Lawrence,
> 
> I can't give you answers to all your questions, but to tell a (linux/unix)
> host which DNS server to use, you would enter the ipv6 address in the
> /etc/resolv.conf file.
> 
> And then i doesn't matter if the DNS server is on a different subnet, as
> long as you can route traffic to that subnet.
> 
> I hope that this will help a little bit.
> 
> Kind regards,
> @
> 
> 
> >In a dual stack network, a dual stack node can find your DNS servers via
> >configured IPv4 addresses, and get both IPv4 and IPv6 addresses back
> >for dual stack targets, after which IPv6 traffic can proceed.
> >
> >How does an IPv6-only node find the DNS server(s). I assume this is
> >where the new anycast addresses come in.

You would configure /etc/resolv.conf or equivalent configurations, or
utilize DHCPv6(?)..

> >Will the IPv6 only node try
> >to connect to the magic IPv6 DNS anycast address, and the "closest"
> >IPv6 capable DNS server will respond?

Note that OCCAID (http://www.occaid.org/rdns.php) is running an anycast
routed resolver IPv6 DNS for its downstreams. We're not using anycast
addresses of IPv6, in fact what we are doing is almost the way it is
done in IPv4 for root/gtld-servers anycast.

BGP routing determines the ~"closest" server as you would guess.

But the client devices must still manually configure this server in
their respective TCP/IPv6 configuration.

> >
> >How does that DNS node know to respond to that anycast address?
> >Do you manually assign the IPv6 DNS anycast address to every DNS
> >server?

You configure named.conf to source its queries from a unicast-routed
IPv6 address, while listening on all addresses, which includes anycast.

> >
> >Would this still work if the "closest" DNS server was beyond your router?
> >Can the DNS anycast address route out through your firewall?
> >
> >Is there some other way to manually specify the addresses of your
> >preferred DNS servers on an IPv6-only node?
> >
> >Can you block the DNS anycast address from going beyond your
> >gateway to insure that internal nodes will get your internal DNS server,
> >and not some extenal one?

All of this doesn't really matter -- it is really up to how you or any other
intermediate networks filter or route the traffic to their closest anycast
server.. Once the DNS server information is disseminated like in IPv4 DHCP,
it really doesn't matter where that server is, as long as it is routed
somewhere, reachable, and can respond back to you with a correct answer.

-J

-- 
James Jun                                            TowardEX Technologies, Inc.
Technical Lead                      Boston IPv4/IPv6 Web Hosting, Colocation and
[EMAIL PROTECTED]            Network design/consulting & configuration services
cell: 1(978)-394-2867           web: http://www.towardex.com , noc: www.twdx.net
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