Big_Brother

I have two network cables connected to my PC. One belongs to a Windows domain and provides Internet. The other one provides only Internet. Both of the connections do not require proxy to access the Internet. When both connections are enabled on the PC, I cannot see PCs on the Windows domain and my email does not work. When I disable the second connection everything goes back to normal. Is there a software that will ask me for each network request which connection should handle the request? I am also open for any other solution.