There seems to be a bit of confusion over which DNS servers the IPv6-enabled customers are supposed to be using. I found that using the regular recursive DNS servers (-4 dnsr{1,2}) from the non-IPv6-enabled-2Wire directly on my OS X does work on resolving AAAA records, but ONLY if the auth NS servers for the domain zone in question are available over IPv4.

Please note that in the scope of this discussion, an “IPv6-only domain” is a domain name that can be resolved ONLY via an IPv6 network, since the NS servers of the zone in question are available ONLY via IPv6. A more correct term would probably be a “domain name within an IPv6-only domain zone”.

Surprisingly, using dns6rd{1,2} does NOT resolve IPv6-only domains, i.e. those that require IPv6 to access its auth NS servers. Making it pretty obvious that dns6rd{1,2} are NOT dual-stacked. WTF? So useless! What’s the purpose of the dns6rd servers if they can’t access IPv6-only domain zones, where the regular dnsr{1,2} already work for AAAA as is?

Seems like dns6rd{1,2} are already EOL at this point, as they offer no advantage whatsoever over -4 dnsr{1,2}, and there’s not even any -6 dns6rd{1,2}, plus they don’t seem to be much of anycast, either.

Using the -6 dnsr{1,2} does resolve IPv6-only domains, but the servers are very far away from me, so they’ll be breaking all those unicast DNS-based CDNs in a snap (e.g. Google, Akamai etc).

Is there an ETA on when either my -4 dnsr{1,2} anycast would be dual-stacked, or the -6 dnsr{1,2} would be anycast’ed locally, instead of going back to Texas or whatnot?

Here are my sample traceroute runs from San Jose, CA. (Note that there’s no -6 dns6rd{1,2}, as already mentioned above.)

[code]
% echo traceroute{\ -IM5,6\ -l}\ -w2\ dns{r,6rd}{1,2}.sbcglobal.net | xargs -n4 | sh
traceroute to dnsr1.sbcglobal.net (68.94.156.1), 64 hops max, 60 byte packets
5 12.83.39.137 (12.83.39.137) 3.464 ms 2.178 ms 1.997 ms
6 151.164.102.35 (151.164.102.35) 3.796 ms 3.268 ms 3.058 ms
7 dnsr1.sbcglobal.net (68.94.156.1) 3.347 ms 2.834 ms 3.005 ms
traceroute to dnsr2.sbcglobal.net (68.94.157.1), 64 hops max, 60 byte packets
5 12.83.39.137 (12.83.39.137) 3.155 ms 1.865 ms 1.857 ms
6 dist1-10g1-2.snfcca.sbcglobal.net (216.102.176.225) 3.463 ms 4.992 ms 3.052 ms
7 dnsr2.sbcglobal.net (68.94.157.1) 3.343 ms 3.147 ms 3.004 ms
traceroute to dns6rd1.sbcglobal.net (99.99.99.53), 64 hops max, 60 byte packets
5 12.83.39.137 (12.83.39.137) 3.051 ms 1.846 ms 1.838 ms
6 12.83.49.11 (12.83.49.11) 44.498 ms 44.029 ms 44.040 ms
7 ppp-151-164-39-47.rcsntx.swbell.net (151.164.39.47) 44.457 ms 43.917 ms 46.538 ms
8 dns6rd1.sbcglobal.net (99.99.99.53) 44.564 ms 44.067 ms 44.076 ms
traceroute to dns6rd2.sbcglobal.net (99.99.99.153), 64 hops max, 60 byte packets
5 12.83.39.137 (12.83.39.137) 3.059 ms 1.907 ms 1.769 ms
6 bb2-p2-0.snantx.sbcglobal.net (151.164.42.128) 44.352 ms 43.849 ms 43.905 ms
7 ppp-151-164-39-47.rcsntx.swbell.net (151.164.39.47) 43.946 ms 43.907 ms 43.753 ms
8 dns6rd2.sbcglobal.net (99.99.99.153) 43.984 ms 43.546 ms 43.679 ms
traceroute6 to dnsr1.sbcglobal.net (2001:1890:fff:840::10) from 2602:306:37cY:YYY0::1, 30 hops max, 12 byte packets
1 2602:300:c533:1510::5 (2602:300:c533:1510::5) 3.121 ms 2.098 ms 1.968 ms
2 2001:1890:ff:ffff:12:122:100:82 (2001:1890:ff:ffff:12:122:100:82) 47.929 ms 47.989 ms 47.585 ms
3 2001:1890:fff:820:12:122:243:1 (2001:1890:fff:820:12:122:243:1) 47.562 ms 47.671 ms 47.714 ms
4 dnsr1.sbcglobal.net (2001:1890:fff:840::10) 47.718 ms 47.714 ms 47.818 ms
traceroute6 to dnsr2.sbcglobal.net (2001:1890:fff:841::10) from 2602:306:37cY:YYY0::1, 30 hops max, 12 byte packets
1 2602:300:c533:1510::5 (2602:300:c533:1510::5) 2.224 ms 1.868 ms 2.016 ms
2 2001:1890:ff:ffff:12:122:100:82 (2001:1890:ff:ffff:12:122:100:82) 47.57 ms 47.429 ms 47.747 ms
3 2001:1890:fff:820:12:122:243:1 (2001:1890:fff:820:12:122:243:1) 47.372 ms 47.382 ms 47.31 ms
4 dnsr2.sbcglobal.net (2001:1890:fff:841::10) 47.834 ms 47.489 ms 47.508 ms
traceroute6: nodename nor servname provided, or not known
traceroute6: nodename nor servname provided, or not known
[/code]

[code]
% traceroute -I 12.83.49.81
traceroute to 12.83.49.81 (12.83.49.81), 32 hops max, 60 byte packets
5 12.83.39.137 (12.83.39.137) 3.015 ms 1.799 ms 1.976 ms
6 12.83.49.81 (12.83.49.81) 1.908 ms 1.682 ms 1.517 ms
[/code]

written for, and discussion at, http://www.dslreports.com/forum/r26902814-IPv6-6rd-DNS-Cannot-resolve-IPv6-only-zones.