I have Sixxs tunnel registered back a long time ago but never had the right software/hardware until now when I built my own FW pc.
# apt-get install aiccu
The upper screen will show up asking SixXS username and password.
Once set up, a aiccu daemon will try to establish connection and set up interface "sixxs" like this…
Once setup, it's time to "advertise" IPv6 addresses to our network. This will be accomplished with RADVD package.
#apt- get install radvd
The daemon won start without configuration in /etc/radvd.conf which we have to create. The content in my case is
interface eth0
{
AdvSendAdvert on;
prefix 2001:15c0:65ff:836d::/64
{
AdvOnLink on;
AdvAutonomous on;
AdvRouterAddr on;
};
};
If starting radvd refuse to start and showing message like "IPv6 forwarding seems to be disabled" then we have to correct that.
echo 1 > /proc/sys/net/ipv6/conf/all/forwarding
In my case hawing Shorewall6, I had to fix shorewall configurations first.

