Comment by bscphil

I'd be rather surprised if IPv6 hasn't done some damage to the idea of IP blocking on the whole. It's possible, even as a residential Internet user, to request a /56 or /48 automatically with DHCPv6 Prefix Delegation. I have a /56 with Comcast. That's potentially up to 65536 /64 blocks, just from a residential user, so if you're going to attempt IP filtering for IPv6, it's got to be a lot smarter than swapping out your single-IP blocking for /64 blocking.