IPv6

Nginx configuration - Listen

listen [::]:80; #IPv6 ONLY on Nginx >= 1.3, but IPv6+IPv4 on previous Nginx versions
listen *:80 # IPv4 only, since Nginx 1.3 it is necessary to state it explicitely if we really want IPv4

In Nginx 1.3 net.ipv6.bindv6only was turned on by default, so if you want both IPv6 and IPv4, you have to state it both in config.

Nginx documentation for listen

Ping

ping6 ipv6.google.com