This is not strictly a Linux related post, but I really need to get some feedback on a computer/software security issue and hope there is someone here who may be able to help.

I am using a program (that isn’t available in Linux) that requires an active internet connection in order to check its end-user license key and to access data. These connections have to be allowed in order for the program to function. However, I don't want some of the information I put into the program to be sent over the internet.

Is there a way to block some outbound data transmission while allowing other data to go through unhindered?

I have considered a firewall, but the problem is that I am not sure what connection requests to allow and which ones to deny.

Another solution may be to set up two computers and have one computer access the internet and then send the data to a second computer that would not be connected to the internet.

Can anyone envisage a simple solution that would allow me to isolate a computer from the internet, while still allowing it to get information from the internet through another computer?

Thanks

PS. Computer is running Windows XP