Enter this router's node name or IPv4 address. This will used to construct a 6to4 site prefix that can be advertised to hosts on the interfaces attached to the IPv6 site. This address must be a valid, globally unique IPv4 address configured on the router's interface to the IPv4 network.      

If an IPv4 address is configured on the node, the address appears as a default. Press [Enter] to accept the default.