ping
Most network administrators are very familiar with the ping utility and are likely to use it on an almost daily basis. The basic function of the ping command is to test the connectivity between the two devices on a network. All the command is designed to do is determine whether the two computers can see each other and to notify you of how long the round-trip takes to complete.
Although ping is most often used on its own, a number of switches can be used to assist in the troubleshooting process. Table 3 shows some of the commonly used switches with ping on a Windows system.
|
Option |
Description |
|---|---|
|
ping -t |
Pings a device on the network until stopped |
|
ping -a |
Resolves addresses to hostnames |
|
ping -n count |
Specifies the number of echo requests to send |
|
ping -r count |
Records route for count hops |
|
ping -s count |
Timestamp for count hops |
|
ping -w timeout |
Timeout in milliseconds to wait for each reply |
ping works by sending ICMP echo request messages to another device on the network. If the other device on the network hears the ping request, it automatically responds with an ICMP echo reply. By default, the ping command on a Windows-based system sends four data packets; however, using the -t switch, a continuous stream of ping requests can be sent.
ping is perhaps the most widely used of all network tools; it is primarily used to verify connectivity between two network devices. On a good day, the results from the ping command will be successful, and the sending device will receive a reply from the remote device. Not all ping results are that successful, and to be able to effectively use ping, you must be able to interpret the results of a failed ping command.