This week I was testing jumbo frames in our lab environment and had some issues with the vmkping command and not default TCP/IP stack. In our lab environment we use separate TCP/IP stacks for the vMotion and Provisioning VMKernel interfaces. With the vmkping command it’s possible to pass this TCP/IP stack as an argument.
However, when using the vmkping command I ran into a problem. The command would not work, the error message was: “vmkernel stack not configured.”
I’ve double checked the TCP/IP stack name in the vSphere Web Client and it was correct.
To be sure I also checked the VMkernel configuration on the ESXi host itself with the esxcfg-vmknic command and that is when I discovered the problem. The Web Client shows the TCP/IP stack with capital letters while the actual name on the ESXi host is small letters only!
I changed the vmkping command to use the name as shown on the host and this time it worked!
Conclusion: when using the vkmping command with a not default TCP/IP stack use the name as shown with the esxcfg-vmknic command and not as shown in the vSphere Web Client.