I have a Windows 7 Pro machine and have two assigned IP addresses. One is the local IP address, set as a static, reserved on DHCP server, and needed for authentication to accesses certain network programs. This is the one I need to be the primary. However, I needed to add a second IP address, a 10.x.x.x which connects to another server to allow access to a remote program. The problem is, after adding this 2nd address, I cannot log in to MS Lync (which is not the program requiring the 10.x.x.x address). Running the ipconfig command reveals the 10.x.x.x is the primary IP address, with the 192.168.x.x address being listed secondarily. As soon as I delete off the 10.x.x.x address, MS Lync works again (by works I mean it logs in, otherwise it won't).