If I want to keep XP firewall openned, how to make all packets (TCP, UDP, ICMP) routing to the external interface in my NAT ? Does the XP firewall drops all packets , or only ICMP packets? is there any solution for that?
Windows XP firewall can be configured to do drop/pass the packets you want. On the other hand WinpkFilter driver processes packets before TCP/IP stack and built-in firewall so basically you can make routing yourself.