PING Usage and Limitations
Ask any network pro what kind of test they try first when taking on a trouble ticket… Inevitably, they’ll say, “I send a Ping.” But why use Ping?
Ping is a protocol used to verify device availability, response time, and packet loss in a network by sending ICMP (Internet Control Messaging Protocol) Echo Request frames to an end network device and listening for the Echo Reply frames from the device. In other words, if the end device receives and returns the Ping, then you have connectivity to the device.
Ping is the first tool of choice because it is easy to use, available on virtually any networked device, and quickly verifies connectivity. Computer problems are often incorrectly blamed on the network. When a Ping is successful, with a normal response time (usually less than 50 ms), it indicates that all the networking devices between you and the destination are communicating properly, including the network adapter in your computer, your router, and whatever devices exist on the internet between the router and destination. This means the problem is probably not with the network.
Good Ping results are reliable; however, bad results can be caused by many different issues. If a host does not reply, the problem could be that there was no path (route), the device was offline or too busy to respond, the ping packet was discarded, ICMP was blocked (e.g. in Windows 10 by default), name resolution failed …and so on. Therefore, an unsuccessful Ping means it’s time to investigate further.
You can try to isolate the cause of the problem by checking other network connections. For example, you can Ping your loopback address (127.0.0.1) to confirm the network adapter is working properly on your device, or Ping your router (aka default gateway) to verify local network operation or Ping a reliable service like www.google.com.
Sometimes network devices are configured to block or discard ICMP traffic due to security concerns, and as a result, these devices will not return a Ping. In this case, a more reliable method is to verify the connection using a TCP (Transmission Control Protocol) Port Open command on an open port such as port 80 (HTTP).
Tracert (or Traceroute) is another common application that can identify where the connection stops in the network path. This method provides a list of all the Layer 3 routers (and time for each hop) in the network path from source to destination.
These tools and others can help you get to the root cause of a network problem.
Where does the word Ping come from?
Some people say it is an acronym for “Packet InterNet Groper,” while others say the word “Ping” is based on the sonar sound.