Firewall bypassing tool

[d_fence <d_fence () gmx net>]

Hi all, 
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?
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