Long story short, I'm embarrassed to say that this is the first time I've really delved into IPv6. Our ISP only offers IPv4, and our school network was around 200 total devices. That's the largest network I support, so there simply hasn't been any pressing reason to worry about it yet. But, enter a large donation of 25 Mac Pro 4,1 (now 5,1, of course!) machines, and add a few staff devices, and suddenly we are really pushing the IPv4 address limit so I figured I would start looking into implementing IPv6 on the LAN and setting at least a subset of devices into an IPv6 only mode so they don't eat-up our IPv4 addresses. I would prefer to continue utilizing our existing primary router, an Airport Extreme, since it integrates so well with Mac OS X Server, but if it won't work, it won't work, so feel free to suggest alternatives. Setting up the tunneling was fairly straight-forward, as was getting a test Mac to connect via IPv6 with IPv4 disabled. I set up IPv6 on the AE router to connect "Automatically" and the IPv6 Mode to "Tunnel" and *bang*, it sort of works. Router has 7.6.8 firmware (latest available for that model). However, a LOT of domains won't resolve. Many will, but many won't. Googling around, it appears that this is a common issue. So I thought I would ask here before I spend untold hours trying circumvent either a) my own ignorance or b) a function that simply won't work as intended. Has anyone had luck getting the Tunneling on AE routers to be reliable? If so, how did you make it work? (Remember, I want to totally disable IPv4 on at least a subset of devices on the LAN). Thanks for any tips you may have!