Long story short, I am having issues with IPv6 using a 6rd tunnel with my ISP, Charter Business. They offer a 6rd tunnel that I think I have properly set up, but the server doesn’t reply to every IPv6 ...
First 6to4: 6to4 allows IPv6 Packets to be transmitted over IPv4. It's used to connect two IPv6 'islands' - not enable IPv4 to talk to IPv6 or vice versa. IPv6 address 2002:AABB:CCDD:: becomes IPv4 ...