Dial-up connection detection

Question

How can I make an assemply (exe) with c#.net resides in system tray waiting for dial-up connection (as an example displays message box when connection to internet succeeded). I found that to place it on system tray I must use notifyIcon class ,to detect connection there is proberty called network in system.Windows.Forms.SystemInformation. Network but at all times it returns True ??? How kan I detect connection ,please ?