Update Mar 23 ‘21: Improve the stability of IPv6 tunnel. I like IPv6, but Cox’s IPv6 network is suboptimal. I like the idea of a VPN providing millions of IPv6 addresses to its clients. Wireguard, it seems, is the obvious choice for creating an IPv6 VPN. Yes, I did set up Wireguard servers before using Debian, /etc/network/interfaces and wg-quick.