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Re: Geographic map of IPv6 availability

  • From: Kevin Day
  • Date: Sat Oct 06 00:54:30 2007

On Oct 5, 2007, at 10:38 PM, Kevin Loch wrote:

Nathan Ward wrote:
On 6/10/2007, at 3:18 AM, Stephen Wilcox wrote:
Given the above, I think there is no myth.. !
That's because the 'v6 network' is broken enough that putting AAAA records on sites that need to be well reachable is a bad idea.
For example, due mainly to Vista's 6to4 tunnelling stuff (based on researching a random sample of users), I'd lose about 4% of visitors to my web-sites if I were to turn on AAAA records.

Has anyone who was using AAAA records for a site turned them off due to
reachability problems?

Yes. We tried it on one of our client's rather high profile sites and had to turn it off because of exactly that problem.

We found a few friendly tech savvy users who were experiencing the problem and followed up with them the best we could. The reasons for the problems were:

Some had inadvertently enabled 6to4 (one admitted remembering playing with it after reading about it on slashdot, then forgot about it).
Some had installed one vendor's firewall that was trying to be proactive and firewall v6 things as well. We never determined if this was default behavior or not, but if you checked the "Firewall v6 traffic" box, it enabled the whole v6 stack just so that it could firewall it.
Some we were never able to figure out why it broke connectivity for them. Theories about transparent proxies doing the wrong thing, broken resolvers or other issues floated up, but we could never pin them down.

It definitely wasn't in the order of entire percentage points of users being unable to access the site, but it was a non-zero number and enough to make the site owner want the AAAA records pulled.

I talked about this briefly at and it's one of the things we plan on trying to measure when we finally get it up and running.

-- Kevin