IPv6 basics: addresses that build themselves

The idea

A laptop, a phone and homeRouter, a Router, share one network. You will see IPv6 at work: a card gives itself an address, finds its neighbours with ICMPv6, and learns its network's prefix from the router.

Steps

1. Two IPv6 addresses on one card

   Nobody typed an IPv6 address into the laptop. List its IPv6 addresses and its card's MAC address, to see where they came from.

   laptop:~# ip -6 addr show dev eth0
   laptop:~# ip link show eth0

2. Talking with link-local addresses

   Link-local addresses work with no router at all, so neighbours can always talk. Ping the phone's link-local address bare, then with the laptop's card after a %.

   laptop:~# ping -c1 -W2 fe80::42:aff:fe00:10b
   laptop:~# ping -c1 -W2 fe80::42:aff:fe00:10b%eth0