When troubleshooting a network, ping can be a useful tool for verifying client/network reachability. All Cisco Meraki devices provide a ping Live Tool, however the behavior of that tool varies by platform. This article will identify those differences.
ICMP Echo Request (Ping) vs. ARPing
A traditional ping involves sending an ICMP Echo Request message to the IP address provided. If the client receives the message, and is not configured to block ICMP, it will reply with an ICMP Echo Reply. Once received by the original device, the ping is completed, and a round trip time (RTT) can be calculated which provides an idea of latency between the two devices. ICMP allows reachability testing between both local and remote devices, such as over the Internet or a VPN. This is used by the MX Security Appliance and Z1 Personal Gateway.
ARPing uses ARP (Address Resolution Protocol) to determine if a local device is on the network. All devices will reply to ARP, making this a more reliable test, however it can only be used within the same subnet. This is used by MS Switches and MR Access Points.
Pinging from Live Tools
To perform a ping from a specific device, navigate to the status page for that device, and find Ping under Live tools.
- MX - Monitor > Appliance Status
- MS - Monitor > Switches > (Select a switch)
- MR - Monitor > Access points > (Select an AP)
On an MX Security Appliance, ping can be provided with a DNS hostname, IP address, or client MAC address. Then click Ping to begin the test. The section that appears will include information on the percentage of packets lost, average latency, and provide a graph of the latency to the device while the test is running. If there is no response, the ICMP Echo Request either wasn't able to reach the destination, or the ICMP Echo Reply wasn't able to return to the MX.
For MXs running firmware MX15.11 or below, the source IP that MX uses while pinging a destination is the MX IP of highest VLAN ID. If the destination is across a VPN, the MX uses the MX IP of highest VLAN ID participating in VPN.
For MXs running firmware MX15.12 or above, there is a drop down to select the source IP address for pinging any destination from the MX.
Note: Pings from the MX Ping Live Tool will follow the same routing as clients that are connected to the LAN of the MX.
On MS Switches and MR Access Points, ping can be provided with the name or MAC address of a connected client. Then click Ping to begin the test. The section that appears will include information on the percentage of packets lost, average latency, and provide a graph of the latency to the device while the test is running. If there is no response, the client most likely doesn't exist or isn't currently connected.