I want to build a software Web server on a Raspberry Pi running Linux and then place it directly between an existing firewall and a cable/ADSL ISP modem. The idea is that if via my dynamic IP I could access the Web server on my Pi but otherwise all traffic would flow through to the existing firewall and then through to my home system. I do not want to have to open any ports/make any modification in the existing firewall. The Raspberry will have two NIC's - the on-board one and then one that works through the USB. Is this possible and if so how would I do it? I know there are lots of firewall apps for Linux - not sure if that would be necessary here but if it is then I would be willing to implement it. Again, I do not want to make any changes to the current firewall, the only traffic I want to interrupt is to my Web Server and if it has to be on some strange port not usually associated with a Web Server so be it. Also if there is a 'Linux software appliance' distribution that I could install on the Pi that would also let me add a Web Server that would be ok as well.