Configuring VLANs within vSphere is a simple enough task, however, testing outgoing ICMP traffic between hosts is a must when you find yourself unable to communicate with another vmkernel port on another host. Using the vmkping command, we are able to test outgoing traffic on a specific vmkernel port, perfect for those attempting to troubleshoot connectivity issues on different subnets and/or vSwitches.
Testing Basic Network Connectivity
- Connect to an ESXi host via SSH.
- Via command shell, run the below command (where x.x.x.x is the hostname or IP address of the server that you wish to ping):
Shell1# vmkping x.x.x.x
In my example below, I test connectivity between the Management Networks on two ESXi hosts in my lab. Specifically, I connect to Host A (192.168.20.101) via SSH, and ping Host B (192.168.20.102):
Testing Network Connectivity via a Specific VMkernel Port
ESXi 5.1 and up allows us to test outgoing ICMP traffic on specific vmkernel ports by adding the -I switch, followed by vmkX (where X is the VMkernal number):
# vmkping -I vmkX x.x.x.x
In my example below, I test ICMP traffic between two VMkernel ports which have been configured for iSCSI traffic (vmk1 on both hosts). Specifically, I SSH on to Host A and test ICMP traffic between the specific VMkernel ports (Host A = 192.168.25.101, Host B = 192.168.25.103):