On iOS4.1 there is ZERO builtin capability to view or configure ipv6 settings. You all probably know that iOS4.x has a working ipv6 stack that will autoconfigure itself on a wireless network if you give it an ipv6 router advertisement. This is a glaring gap in native iOS functionality. Hopefully Apple will fix this in iOS4.2, but meanwhile modders should have at least a commandline app to handle this situation. I do see that from the cmdline, you can use ndp -a to view ipv6 addresses. But netstat, ifconfig, route, and python socket etc are all ipv6-ignorant on iOS with the cydia packages that you would think would display or configure ipv6.