Custom Proxy Connection

Here's the situation: I have two computers, both are connected to the Internet with different IPs. I need to run some client software to connect to a server, but I want one of the computer uses the other ones IP to connect. To be more specific, the server authenticates the client by its IP. I can authenticate my desktop computer as it has a static IP, but for my laptop computer that usually has a dynamic IP, there's no way I can directly connect it to the server. The only way is to go through the desktop computer. It is much similar to browse the web site through a proxy. However, there isnt' anyway I can configure the client software to use a proxy. So I need a program that will capture the client software's outgoing packets and send it through my desktop computer. I assume this is achievable with a proxy server installed on the desktop computer. If not, I would like to know what other way to go around this or whether this is doable. Please be specific about what you can do to solve this problem. In order for me to award this project, I need to be convinced that you can deliver exactly what I want. Thanks. After receiving a few responses, I think I need to make my project a bit more clear. The two computers are not on the same physical network. They can not be physically connected. I intend to use the laptop anywhere. They can both connect to Internet by themselves, but not together sharing a physical cable. ## Deliverables 1) Complete and fully-functional working program(s) in executable form as well as complete source code of all work done. 2) Installation package that will install the software (in ready-to-run condition) on the platform(s) specified in this bid request. 3) Complete ownership and distribution copyrights to all work purchased. ## Platform Windows 2000