You want to check if a computer is online and gauge its response time.
Send a ping message.
A ping message contacts a device at a specific IP address, sends a test message, and requests that the remote device respond by echoing back the packet. You can measure the time taken for a ping response to be received to gauge the connection latency between two computers.
Despite the simplicity of ping messages compared to other types of network communication, implementing a ping utility in .NET requires a significant amount of complex low-level networking code. The .NET class library doesn’t have a prebuilt solution—instead, you must use raw sockets.
However, at least one developer has solved the ping problem. Lance ...