The ESXi vmnic# is greyed-out on the vSwitch

Products

• VMware vSphere ESXi

Issue/Introduction

• One or more vmnic interfaces on the ESXi host displays as inactive/greyed-out status instead of active green state.
  
  
  • Navigate to ESXi Host--> Configure--> Virtual switches--> Expand virtual switch and Uplinks.

• However, "vmnic#" adapter status reports active on ESXi host.
  
  
  • ESXi Host--> Configure--> Network adapters.
    
    

Environment

VMware vSphere ESXi

Cause

This issue is typically caused by one of the following factors:

• Physical link status down for the specific vmnic.
• vmnic brought down administratively.
• Faulty uplink.
• Cosmetic issue from the vSphere UI.

Resolution

Verify the following to make sure the vmnic is active and operational.

• Check vmnic Link and admin status.
  
  
  • Login to ESXi host cli with "root" user account and run the following command.
    esxcli network nic list

• • • If the "Link Status" is down:
      • Verify the ESXi host physical nic status through "ILO/IDRAC etc" to identify Link connectivity status.
        
        
    • If the "Admin Status" is down:
      • Verify whether the vmnic was intentionally disabled for a specific reason (e.g., the required network is unavailable, a faulty NIC, port flapping, or other hardware issues etc.). If there is no reason for it to be offline, proceed to administratively bring the interface back up by running the following command.
        
        • esxcli network nic up -n <vmnic#>
          
          
• Validate the traffic for the specific vmnic through esxtop.
  • Log into the ESXi host CLI as 'root' and execute the command below to determine if TX/RX traffic is actively flowing or if no traffic is present
    
    • esxtop

• • Alternatively, run a packet capture to determine if active traffic is passing through the interface.
    • Reference KB to perform packet capture "Packet capture on ESXi using the pktcap-uw tool".
      
      
• Host reboot checks for the cosmetic issue:
  • If the host uptime is high, perform a reboot by placing it into a maintenance mode.