Change NIC speed and duplex setting to AUTO in ESX4 using PowerCLI


When you install VMware ESX 4 by using the default installation method from for example the DVD, the NIC speed  and duplex setting are set to fixed for each NIC. This means that the network switch port must be set to fixed too. In VMware ESX 3 the default NIC mode was Auto Negotiate In the vCenter clients this looks like:


You can easily change the NIC speed and duplex settings to auto Negotiate for all NICs in the ESX host by using PowerCLI. This can be done by using the  following one-liner: 

Get-VMHostNetworkAdapter | Set-VMHostNetworkAdapter –AutoNegotiate

Be sure when you execute this command in production environment, that the VMware ESX hosts is in maintenance mode!



1 thought on “Change NIC speed and duplex setting to AUTO in ESX4 using PowerCLI”

  1. Thanks for setting up this article.

    One issue: Your command also tries to update settings on e.g. vmkernel. So some errors are displayed during the execution.

    The command below filters out only the vmnic’s, and no confirmation is asked during the execution. (change -Confirm:$True to enable confirmation.

    Get-VMHostNetworkAdapter | where {($_.Name -match “vmnic”)} | Set-VMHostNetworkAdapter –AutoNegotiate -Confirm:$False


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