For the few who plan to use a Nokia IP-xxxx box with IPSO v3.8 or higher as IPv6 tunnel end-point with SixXS here is a tiny howto: 1. Create an unnummbered IPv6 tunnel to the alllocated SixXS pop. Config ==> IPv6 Configuration => IPv6 in IPv4 Tunnels (Only fill in the IPv4 addresses!) 2. Select the new tunnel (tun0c0 for example) and add a new prefix which will be the IP address assigned to your end of the SixXS tunnel. (For example: 2001:960:2:511::2/64) 3. Set your default gateway to the SixXS pop IPv6 address. And that should be basically it. (I got it working on IPSO version 3.8.1-BUILD033 ) But if you try to add the prefix to the tunnel straight off in step 1 you will not get it configured. Wether this is a bug or a design issue is not entirely clear to me. But I hope this note may be usefull to someone someday.