Re: Firewall bypassing tool

[Michael Katz <mike () procinct com>]

At 11/1/2002 03:28 AM, d_fence wrote:

> I read sometime ago about bypassing the firewall filters which block incoming
> (initializing) SYN packets, by sending for example a SYN-FIN packet and
> establishing that way a connection to a blocked port.. Now  I`m trying to
> check wether my firewall would let through such packets, and so I`m searching
> for a tool which would does this.. Do you know any such tools?

This seems too obvious, but....

How about Fyodor's nmap?  You can obtain it from http://www.insecure.org/nmap.

One of the options for scanning is -sF, which will send SYN-FIN 
packets.  You can also use -sA, which will send SYN-ACK packets.

There are also tools like hping (http://www.hping.org) which can be used to 
test your firewall in a similar manner.

Michael Katz
mike () procinct com
Procinct Security