https://wiki.koumbit.net/DnsTunnel
http://www.splitbrain.org/blog/2008-11/02-dns_tunneling_made_simple

http://thomer.com/icmptx/
http://etbe.coker.com.au/2011/01/12/icmptx/

http://hideandhack.blogspot.pt/
http://www.youtube.com/watch?v=zsyMp5DE-J0
http://www.hideandhack.com/
http://www.hackguide4u.com/2010/03/icmp-tunneling.html

https://en.wikipedia.org/wiki/ICMP_tunnel

https://home.regit.org/netfilter-en/secure-use-of-helpers/

http://ubuntuforums.org/showthread.php?t=1476832

http://www.over-yonder.net/~fullermd/rants/bsd4linux/01

http://www.libcrack.so/category/freebsd/

http://www.jnocook.net/linda/index.htm

https://forum.openwrt.org/viewtopic.php?id=27354
ver também este IMPORTANTE
https://trac.torproject.org/projects/tor/wiki/doc/OpenWRT
http://outflux.net/geoloc/


# cd /etc/openvpn
# mkdir easy-rsa
# cp -R /usr/share/doc/openvpn/examples/easy-rsa/2.0/* easy-rsa/
# chmod -R +x easy-rsa/