The Types of Ping Commands

The "ping" command is one of many tools in a network technician's toolbox, and it is one of the most useful. Ping is typically used to verify that a link exists between two machines, using either the IP address of the target machine or the hostname of the machine. However, ping can accomplish more than just basic link verification by using command switches that reconfigure the command to behave a bit differently.

In its most stripped down form, the ping command consists of just two words – "ping ," where "" is either the IP address or the hostname of the target device. The official full syntax is as follows:

ping [-t] [-a] [-n count] [-l size] [-f] [-i TTL] [-v TOS] [-r count] [-s count] [[-j host-list] | [-k host-list]] [-w timeout] target_hostname_or_IP

The various switches and parameters result in different types of ping commands.

When you issue a ping command with the "-t" switch, you are issuing a "ping forever" command. Ping will continue until you manually stop it with a "Ctrl-C," or pause it with a "Ctrl-Break" key combination. The pause will stop ping long enough for you to see the statistics and then resume. Alternatively, you can use the "-n " switch to tell ping to issue "count" pings against the target device.

Another type of ping command performs name resolution on a specified IP address. The "-a" switch tells ping to do this, and the results include the hostname of the targeted IP address. This type of command can help verify that your IP addressing is correct and determine whether your DNS is working properly.

When you specify the "-w " switch on a ping command, you are telling it to wait a certain amount of time, in milliseconds, for a response from the target device. If the target does not respond within the specified time frame, the ping command times out and issues a timeout message in the results. You can use this command on devices that you know will take a while to respond.

The default length of the ping data packet is 32 bytes. If you want to test larger packets, you can use the "-l " switch to specify larger packets. This type of ping command can be used to identify devices along the ping path that have maximum transmission unit (MTU) configuration discrepancies. This command can also help you determine the impact on network performance when large packets are present.