Ping - common reasons for failure
A successful ping involves an echo request successfully traveling from the source to the destination, and an echo reply successfully traveling from the destination back to the source of the original ping. A failure in a ping could take place at any location along that path.
Now the source and/or destination devices may be any network-connected device, such as a PC, mobile phone, router, switch, IP camera or any other such device. For any of these devices, some of the most common failures are listed below.
Failures originating in the source device may be due to:
- lack of a local route to the intended destination
- local access list blocking this specific traffic (for Cisco IOS devices, take a look at this note)
Failures originating on the network between source and destination devices
- routing between the source and destination may not be sufficient to allow for the echo request to reach the destination
- In the event that it does reach the destination, it may be that routing between the destination and source may not be sufficient to allow for the echo reply to reach the original source. Take a look at Routing in both directions.
Failures originating in the destination device may be due to:
- lack of a local route to the source device
- local access list blocking this specific traffic
It is important to keep in mind that a failed ping may actually make it to the destination, and it is the echo reply that has failed. To determine more precisely where the problem lies, use additional tools such as Traceroute.
For a more detailed look at the various responses and their meanings, take a look at Ping - possible ping responses. Also, take a look at Ping - debug commands to help in more deeply troubleshooting ping responses.
For more information about ping, take a look at Ping - troubleshooting concepts