Error: vmnic link down or flapping due to bnxtnet firmware crash on ESXi 8.0
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Error: vmnic link down or flapping due to bnxtnet firmware crash on ESXi 8.0

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Article ID: 452940

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Updated On:

Products

VMware vSphere ESXi 8.0

Issue/Introduction

After updating an ESXi 8.0 host, you may experience the following symptoms:

  • One or more vmnics (e.g., vmnic4, vmnic5) become inconsistent or disconnected.
  • Alerts for "Network uplink redundancy lost" or "Network connectivity lost" are received in vCenter Server.
  • The vmnic link state flaps up and down.
  • In vmkernel.log, you see messages indicating a firmware crash or hot reset:
bnxtnet: bnxtnet_handle_hot_reset: Hot reset async evt: evt_data1 = 0x301bnxtnet_hot_reset_task: Waiting for 1300 msecs for firmware reset completionwaiting for queue flush response

Environment

VMware vSphere ESXi 8.0

Cause

The issue is caused by a firmware crash on the physical NIC. This triggers the bnxtnet driver to initiate a hot reset/recovery process. Common causes include firmware/driver version mismatch or hardware-level issues.

Resolution

To resolve this issue, follow these steps:

  1. Migrate Virtual Machines: Move all running VMs from the impacted ESXi host to other hosts in the cluster using vMotion.
  2. Verify Driver and Firmware Versions: Identify the current bnxtnet driver and firmware versions.
  3. Check Compatibility: Consult the  to ensure the driver and firmware versions are a supported combination.
  4. Reinstall Driver: As a best effort, uninstall and then reinstall the bnxtnet driver on the ESXi host.
  5. Reboot Host: Reboot the ESXi host to reset the hardware and re-initialize the driver.
  6. Engage Hardware Vendor: If the issue persists or the logs consistently show 0x301 firmware reset events, engage your hardware vendor. Provide the vmkernel.log snippets to the vendor for a detailed analysis of the firmware dump.

Additional Information

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