I have 2 new Lenovo X200's. We use static address in our environment. Both machines have IP addresses that are assigned only to them.
I have always assigned Alternate Configurations to laptops incase the user used LAN connection while traveling and such. Windows XP never had an issues with this.
Here is what is happening. The users go to a meeting. I can setup a constant ping to the machine. Whether it be 20-2 hours in length, the ping drops as soon as the user hits space bar, moves mouse and wakes Monitor up. Laptop is set to never sleep when plugged in.
As soon as the keyboard or something is moved to wake Monitor it drops network connection. If I setup the connection as a static/non alternate IP it doesn't disconnect.