A ping, usually refers to a ping test when talking about computers. A ping is a tool that allows one computer to send a packet of data to another computer and record the response. The response is usually measured in seconds. The idea is that the packet reaches the other computer which stimulates the receiving computer to return a packet of data to the first computer. Interestingly enough, the return packet is called a Pong. So much like the game Ping Pong, computers bounce packets of data back and forth. The names however, are not related to the game, they are terms that evolved from the names given to certain sounds. The rest results of the test explain whether or not the receiving computer is capable of responding to the Ping. It is also a tool to see if a computer is real.
Because computers are identified by their IP Address, a ping test can help to determine if an IP Address is genuine. This means that the ping test can help to save energy. The energy savings comes not from running a computer more efficiently but by not allowing data to be sent to a computer that is not responding.
A ping test determines how long it takes for information to travel in one direction along a network or between two computers. It is used everyday in the background of our computers. Each time we download something and our computer advises us that it will take X amount of time for the download to finish, we are experiencing the result of a ping test.
The malicious application of the Ping Test is not unheard of on the Internet. A hacker may attempt to disable a server by inciting a Ping Storm. A ping storm is barrage of data packets that are sent to a server until the server is unable to handle the volume of data and either becomes inoperable or completely and permanently broken. The opportunity for hackers exists when the server is overloaded. They can then bypass security and steal the servers data. A ping storm is also sometimes referred to as a Denial of Service attack (DoS.) It is not uncommon for hackers to utilize Trojans either as a means of stealing the data, and then to use the ping storm acts as a cover up to the initial crime. There is even such a thing as a Ping of Death which is a huge ICMP packet. The Ping of death is sent in smaller packets and as the server tries to reassemble the larger packet it runs out of buffer space and the server crashes or freezes.
The only real defense is to ensure that you have a firewall in place. Even that is not always enough to stop a DoS attack. For personal computers it is best to simply hide your IP Address using a VPN such as hidemyass.com. If your computer IP Address can not be seen your computer can not be attacked except in the most random way… by guessing a random IP Address.