Avoiding tunnels

[Javier Hijas <jhijas () germinus com>]

Hi all,
  I wonder if there is a way to avoid tunnels via fw (v.g. netfilter).
How can I control that an opened port 80 is not used to tunel to a ssh
server listening at port 80?

Thanks

---------------------------------------------------------------------------
EARN A MASTER OF SCIENCE IN INFORMATION ASSURANCE - ONLINE
The Norwich University program offers unparalleled Infosec management 
education and the case study affords you unmatched consulting experience. 
Tailor your education to your own professional goals with degree 
customizations including Emergency Management, Business Continuity Planning, 
Computer Emergency Response Teams, and Digital Investigations. 

http://www.msia.norwich.edu/secfocus
---------------------------------------------------------------------------