http://en.wikipedia.org/wiki/ICMP_tunnel http://www.fosk.it/how-to-bypass-firewalls-or-captive-portals-with-dns2tcp.html http://www.hsc.fr/ressources/outils/dns2tcp/index.html.en http://www.digitalsec.net/stuff/texts/dns-tunnelingv0.2-en.txt