Log InsightScript

esx.problem.net.vmknic.ip.duplicate – Hunting for MAC

Log Insight is a very powerful tool to monitor your environments health status. One of my favorite dashboards to is the “General – Problems” dashboard, which is part of the  “VMware – vSphere” content pack. It comes with Log Insight per default. Because there you can get a great overview of any problems that might be in your vSphere environment.

One of the problems you might see is the “esx.problem.net.vmknic.ip.duplicate” or as it can be seen in the pie chart “net.vmknic.ip.duplicate”. This problem basically tells you there’s an misconfiguration in your environment. Two VMK nics have the same IP address configured. If you click on the pie chart you will get the picture below, with some modifications. The important thing to note here is the logs them self. It tells us there’s duplicate IP addresses detected. What the IP is – Not clearly visible below. For which interface and the owner of the IP address’s MAC address. Now you just need to find out who the owner of the MAC address is. May not be that easy unless we jump over to some PowerCLI action.

esx.problem.net.vmknic.ip.duplicate

Hunting for MAC

I find that the easiest way to do this is be executing a Powershell script. The below script is provided as an example of how this can be done. Note that the script only lists vmk0/vmk1 and vmnic0/vmnic1’s MAC addresses. If you have more VMNics or VMKs you might need to modify the script.

With the list saved as a CSV files you can simple open it and search for the MAC address of the owner and change the IP accordingly to your specification. Easy as pie.

Now that you have that under control, jump back into Log Insight and start finding answers to your next problem. You know Log Insight always delivers. It is what makes your data center run smoothly.

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