NIC information is reporting Speed as "0" and Duplex as "Half"

Products

• VMware vSphere ESXi

Issue/Introduction

ESXi host has a NIC with a Speed is reported as "0" and Duplex setting as "Half", regardless of the actual speed or duplex settings (either auto-negotiated or manually configured).

This may be observed in either the vCenter or ESXi GUI, or CLI via "esxcli network nic list" command.

The NIC is showing a Link Status of "Down".

Cause

If the NIC is reporting a Link Status of "Down", then the actual speed or duplex settings can not be determined since the NIC is unable to communicate with the upstream network devices properly.

The default information is therefore displayed in lieu of the actual, as the actual cannot be determined, and the default is a Speed setting of "0" and a Duplex setting of "Half".

Resolution

This is expected behavior as long as the NIC is down, so proceed by restoring the NIC's connecitvity and confirm the correct information is reported with the NIC in a fully "Up" state.

Note: If the "Admin Status" of the NIC is reported as "Up" in the output of  "esxcli network nic list" CLI command, then the NIC driver is reporting a link state of down upstream of the NIC driver, outside of the ESXi host. Therefore, engage your vendor or network team to troubleshoot the link.

See Network adapter (vmnic) is down or fails with a Failed Criteria Code for more information.