Last week I setup 6to4 on my server which lives inside a local ISP’s colocation facilities. This provided IPv6 connectivity between my home network and the server. The only changes required were a couple of ACL modifications and configuring sendmail to listen on an IPv6 socket. Sadly I did discover that ejabberd cannot listen to both IPv4 and IPv6 addresses on the same port.

For a little experiment I decided to add an AAAA record to www.coverfire.com and see how much IPv6 traffic arrives. I know that the IPv6 Internet is vastly smaller than the IPv4 Internet so I didn’t expect a huge amount of traffic. In order to analyze whatever traffic arrived I captured all IPv6 port 80 traffic for the duration of the experiment.

The results of this experiment were disappointing. Over about 1.5 days there were only five IPv6 hosts which visited the site. One of the five hosts wasn’t even able to establish a TCP connection. From the capture file it looks like the ACKs from my server never arrived at the remote host.  Of the five addresses, four were 6to4 addresses. I found this a little surprising. Also interesting is the fact that there was no traffic from Teredo hosts.

A more interesting question is whether or not adding an AAAA record has caused troubles for people visiting the site via IPv4. See this article for one of the reasons why AAAA records can cause IPv4 users trouble.

For anyone who is interested I have uploaded the quick Python hack I used to analyze the capture file.

ip6.py