nginx now has ipv6 support! Yay! To have it work on Debian, all you
need to do is open up
listen [::]:80 default ipv6only=on;
ipv6only=on here is a bit of a lie - it will listen on both ipv4 and ipv6.
Then, in your
/etc/nginx/sites-available/* files, add
so nginx listens on both.