I have been using ip6 for two days now - but I haven't yet found an answer to this problem by googling. I have been given a tunnel by SixXS, with end points of xxxx:xxxx:xxxx:xxxx::1/64 and xxxx:xxxx:xxxx:xxxx::2/64 (local end). It is currently working from the host on which the tunnel is established. I want to split this block into several subnets, for different (pseudo) sites. (I'm just trying out concepts to learn about ip6.) Firstly does the granting of a tunnel give me the right to use the whole of the xxxx:xxxx:xxxx:xxxx::0/64 network? There is a greyed-out 'request subnet' option on SixXS site, so I am not sure. If I can use those addresses, how can I subnet them? The tunnel end point is /64 netmask, but I would be interested in setting up xxxx:xxxx:xxxx:xxxx:1::0/80 through xxxx:xxxx:xxxx:xxxx:ffff::0/80. Can I do this? (Several websites say that site identification should be done in bits 48-63 of the address - i.e. xxxx:xxxx:xxxx:ssss:nnnn:nnnn:nnnn:nnnn - s: site n: node. Is this correct? Thanks, Chris.