What is PING? And what does it do?

W

The trusted PING command that has been available for years used to be the de-facto standard for seeing if a computer was up and running or if it was down.

Simple example of how to use PING.

In the following example, I have 2 computers connected to my computer network.

The first is a computer at IP Address 192.168.1.102.  It is connected to the network and is currently powered on.

The 2nd computer is at IP Address 192.168.1.101.  It is also connected to the network, but the power is currently turned off.

Ping Success:

To see that the first computer is up at IP Address 192.168.1.102, you would go to the command prompt and type the following command:

ping 192.168.1.102

You can see very clearly that it says that the computer is up and that it sent 4 replies.  You now know that this computer is up and running.

Ping Failure:

What happens though if you try to ping a computer that is connected to the network, but is not currently turned on, or if you ping an IP Address that is not in any way connected to the network.

When I try to ping the computer 192.168.1.101 that is currently turned off, here’s what happens.

ping 192.168.1.101

The message “Request Timed Out” means that ping was unable to find a computer at that IP Address.

So, in this example, I showed a computer that is currently connected, 192.168.1.102, and a computer that is not currently connected 192.168.1.101.

Limitations of Ping

One of the limitations of Ping is that over the years, people (Microsoft) decided that if a computer is trying to ping you, it is probably trying to do you harm.  So, when Microsoft started installing a program called Windows Firewall by default on all new PCs, the trusted PING program became less and less useful as a diagnostic tool.  The reason why is that if you PING a computer with Windows Firewall turned OFF, it will give you the normal “REPLY FROM…” message and show you that the computer is currently up and running, but if Windows Firewall is then turned on, the same computer will respond with “Request Timed Out”.

This is very frustrating for IT people who just need to see if the computers on their network are up or down.

In a future post, we’ll go through a program called ARPING or HARDPING that can get through this limitation, but as you’ll see has limitations itself.

About the author

By admin

Categories

Archives