Another hacked method to do it -- employ frames. Make the www.example.com/webapp URL a frameset with a one pixel top frame (or side, bottom, what have you) and a * for the other frame. the other frame's source is the linux box. It's a rig, admittedly, and isn't the fully correct way to do it, but it'll work. That's how quite a few websites keep you clicking links but only their www.domain.TLD stays in your location bar.