SYSK 22: Detecting a Change in Network Connectivity
The NetworkChange class (new in .NET 2.0 framework) allows applications to receive notification when the Internet Protocol (IP) address of a network interface, also known as a network card or adapter, changes. An interface address can change for a variety of reasons, such as a disconnected network cable, moving out of range of a wireless local area network, or hardware failure. The NetworkChange class provides address change notification by raising events when a change is detected.
For more information, check out http://msdn2.microsoft.com/library/system.net.networkinformation.networkchange.aspx
