I currently claim to support only IPv4. I did ask for an IPv6 allocation, and about a week ago my provider got back to me with a netblock from he.net, but I've been busy, and I have yet to get around to actually playing with the stuff. Besides, we still have north of 900 days before we run out of IPv4 at the current burn rate.[1]
Now, I've read about this 'IPv6 stateless auto-configuration'[2] The idea is that IPv6 routers announce prefixes via ICMP6 once every 10 seconds, and then the client does some math to create the rest of the IP address using the mac address.
I ask my customer what the IPv6 address he has is, and if it actually works. Yup, the address is in my block, and yes, it works. He just needs an RDNS mapping.
Hopefully, my provider will get me the rdns delegation Tuesday or Wednesday.
Easy Peasy.
[1]http://www.potaroo.net/tools/ipv4/index.html
[2]http://www.cisco.com/web/about/ac123/ac147/archived_issues/ipj_7-2/ipv6_autoconfig.html
still no rdns. grumble
rdns now works for IPv6. pester me if you want it.