My Comcast connection only supports IPv4 at this time, at least as indicated by the cable modem which list the "Modem IP Mode" and "DOCSIS MIMO" as "IPv4 Only." Given that, what is the best setting for IPv6 on the RT-N66U? I was going to disable, but wasn't sure if 6to4 would be a better choice. Any suggestions, and I'll admit that IPv6 isn't something I understand well. What issues might come up as a result of disabling IPv6?