2009/06/21

Teredo IPv6 address

I got the following IPv6 address from Teredo on Windows XP:

2001:0:cf2e:3096:0:78f8:24b0:fed5

The command to activate teredo interface is "netsh interface ipv6 set teredo client teredo.ipv6.microsoft.com".

On analysis, 2001:0::/32 is the prefix. Teredo server is provided by Mircrosoft at 207.46.48.150 (cf2e:3096) and the client gateway of NAT is 219.79.1.42 (24b0:fed5). The flag contents are 0 and the port number of the client port is 34567. All these can be found out by ipv6calc -i -q 2001:0:cf2e:3096:0:78f8:24b0:fed5.

One question I have in mind is how can the router serving the public teredo server announce routing prefix properly given that differnet IPv4 addresses can request the services. It is not difficult at all since client addresses are in the least signicant part. Just announce 2001:0:cf2e:3096::/64 will be satisfactory.

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