Inter Process Communication

Question

Hi! I have a two-part application. One part is a graphical Systray utility providing feedback to the user. The other part is a service providing things that requires local administration rights. I´m now searching for ways to communicate between these two (completely independent) processes WITHOUT using TCP/IP. How am I supposed to do this using the .NET framework? There are easy ways to do this using some kind of TCP channel listening on the service but I´m required to perform this without listening on TCP ports... There must be a way of doing this, but I can´t seem to find it... Help please!