I did that and they told me I had to give up v6 for that, so I noped out of that one. I'd rather have the new protocol than be stuck with the old one. If I need a v4 address (which I did to host a game, I was amazed ziggo pulls this on people and they're not required to have huge warning signs like "you're not really getting a normal Internet connection, you're gonna share an IP address with a million people and not be able to use it in the expected way") I'll do ssh forwarding (-R) to my box at XS4ALL.
Yes, Ziggo don't provide dual stack. It is either IPv4-only or IPv6 with CGNAT for IPv4. I'll take IPv4 in that case, wait till the rest of the world has either dual stack or IPv4, and then once the whole world has IPv6 I'll be OK with IPv6-only.
