One of the ip tools that help you determine
whether TCP/IP is functioning and properly configured is Ping.
Ping test utility is an extremely useful diagnostic ip tool
that initiates a simple test of network connectivity
and reports on whether the other computer responds.
If you notice that your computer can't complete a network operation or if
you would like to know of other computer is "alive",
the first question you should ask is whether it can complete any other network operation.
In other words, is your or other computer currently functioning as a member of the network?
The Web ping utility initiates the most minimal test of network connectivity.
It sends a message to another computer that says "Hello, is anybody out there?"
and waits for the other computer to respond.
DOS Attack using Ping
Denial-of-service attacks often use standard TCP/IP connectivity utilities.
The famous Smurf attack, for instance, uses the Ping utility
to unleash a flood of ping responses on the victim.
The attacker sends a ping request to an entire network through directed broadcast.
The source address of the ping is doctored to make it appear that the request
is coming from the victim's IP address.
All the computers on the network then simultaneously respond to the ping.
The effect of the Smurf attack is that the original ping from the attacker
is multiplied into many pings on the amplification network.
If the attacker initiates the process on several networks at once,
the result is a huge flood of ping responses tying up the victim's system.