NetworkInformation
The System.Net.NetworkInformation namespace enables you to gather information about network events, changes, statistics, and properties. You can also determine whether a remote host is reachable by using the System.Net.NetworkInformation.Ping class.
Network Availability and Events
The System.Net.NetworkInformation.NetworkChange class enables you to determine whether the network address or availability has changed. To use this class, create an event handler to process the change, and associate it with a NetworkAddressChangedEventHandler or a NetworkAvailabilityChangedEventHandler. For more information, see How to: Detect Network Availability and Address Changes.
Network Statistics and Properties
You can gather network statistics and properties on an interface or protocol basis. The NetworkInterface, NetworkInterfaceType, and PhysicalAddress classes give information about a particular network interface, while the IPInterfaceProperties, IPGlobalProperties, IPGlobalStatistics, TcpStatistics, and UdpStatistics classes give information about layer 3 and layer 4 packets. For more information, see How to: Get Interface and Protocol Information.
Determine if a Remote Host is Reachable
You can use the Ping class to determine whether a Remote Host is up, on the network, and reachable. For more information, see How to: Ping a Host.