If you're experimenting (or actually using) IPv6, you have to configure some things to have your Pi IPv6 enabled.
First of all make sure ipv6 is enabled (at all) in the kernel. This can be done by adding a line to the file
/etc/modules as mentioned on this page:
sudo nano /etc/modules
Add just a simple line like this at the end:
Afterwards it probably looks like:
# /etc/modules: kernel modules to load at boot time. # # This file contains the names of kernel modules that should be loaded # at boot time, one per line. Lines beginning with "#" are ignored. # Parameters can be specified after the module name. snd-bcm2835 ipv6
Now if your network is configured as
stateless dhcp for IPv6 things just work after a reboot. To know if your network uses
stateful dhcp or
stateless dhcp ask your local network administrator. Chances are he'll answer that no IPv6 is supported at all.
Unless your Pi is the Gateway itself, it should process RA (Router Advertisement) packets (see also this page. So if your Pi is a gateway, stop reading this paragraph.
Execute the following command:
sudo nano /etc/sysctl.d/ipv6-route.conf
Enter the following line in the file:
net.ipv6.conf.eth0.accept_ra = 1
Now reboot your Pi. After the reboot it'll accept RA packets on eth0.
If your network uses
statefull dhcp, and your Pi is not the IPv6 Gateway itself (see this page), the you have to configure
/etc/network/interfaces - otherwise skip this paragraph.
sudo nano /etc/network/services
Add a line like this:
iface eth0 inet6 dhcp
Any place is OK, but you may consider doing this right after the line
iface eth0 inet dhcp, so you'll end up with the following two lines somewhere in the file:
iface eth0 inet dhcp iface eth0 inet6 dhcp