hey, i'm having problems to discover a deepers sense in this setup... why do you set up a firewall that is not between the inet and your only internal computer? i would consider putting 2 nic's in the firewall machine and make it the only computer connected to your router if both computers are connected to the router only the machin where the firewall is running is protected from the internet. the other one has an connection to the router and the inet without a firewall. or am i completly misunderstanding your setup?
Everything's working find except SMB. SMB isn't working at all if the FW is enabled. AFAIK one port (139?) is only for directory listings or similar but I think the problem is something else but an closed port...
you have services on your firewall machine that you access from the other machine or what? you can ping the firewall computer from the other one? best regards luk