get ipv4 wan
------------

$ curl -4 http://ifconfig.co
90.116.135.67
[please limits to 1 req/min]

$ curl https://ipinfo.io/ip
90.116.135.67

$ curl https://ipv4.wtfismyip.com/text
90.116.135.67
[1 request per minute]


get ipv6 wan
------------

$ host livebox.home
livebox.home has address 192.168.1.1
livebox.home has IPv6 address 2a01:cb1d:164:f500:327c:b2ff:fe9e:cf16

get ipv6 host
-------------

$ host arwen.home
arwen.home has address 192.168.1.113
arwen.home has IPv6 address 2a01:cb1d:164:f500:8ff:3eea:a3b2:714e

$ host arwen.home
arwen.home has address 192.168.1.113
arwen.home has IPv6 address 2a01:cb1d:164:f500:3df0:c245:7d7a:26e2
arwen.home has IPv6 address 2a01:cb1d:164:f500:8ff:3eea:a3b2:714e
arwen.home has IPv6 address 2a01:cb1d:164:f500:28af:1644:6308:f13

$ fping6 2a01:cb1d:164:f500:8ff:3eea:a3b2:714e 2a01:cb1d:164:f500:3df0:c245:7d7a:26e2 2a01:cb1d:164:f500:28af:1644:6308:f13
2a01:cb1d:164:f500:8ff:3eea:a3b2:714e is alive
2a01:cb1d:164:f500:3df0:c245:7d7a:26e2 is unreachable
2a01:cb1d:164:f500:28af:1644:6308:f13 is unreachable