via IPv6 tunnel sixxs.org acess wikimedia. In edit mode, all external links force add suffix ".sixxs.org", and save. IPv4 can't acess these links.
see http://en.wikipedia.org/w/index.php?title=Special%3ALinksearch&target=*....
http://toolserver.org/~eagle/linksearch?search=*.sixxs.org&totalwikis=57