[asterisk-biz] Is ISP Blocking VoIP

[trixter aka Bret McDanel]

On Tue, 2006-01-17 at 16:23 -0500, C F wrote:
> Speaking of ssh tunneling, current issue of 2600 (www.2600.com) has a
> very interesting idea on Tunneling over ICMP. The author of the
> article has written a program to do it, mainly for bypassing payment
> on wifis that charge, since they usualy leave ICMP alone. Here is a
> link:
> http://www.cs.uit.no/~daniels/PingTunnel/
> 

DNS is an older means by which this has been implemented.  There was
even a live demo of streaming music over a dns tunnel.  ICMP can be
blocked far more easily than DNS since only some protocols (HTTP for
example) will work proxied via standard means.

Using ICMP as a covert data channel is over a decade old (check bugtrack
archives about a decade ago).  Not saying this is not useful, just that
its not new by any means.

-- 
Trixter http://www.0xdecafbad.com     Bret McDanel
UK +44 870 340 4605   Germany +49 801 777 555 3402
US +1 360 207 0479 or +1 516 687 5200
FreeWorldDialup: 635378
http://www.sacaug.org/ Sacramento Asterisk Users Group
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