vmnic disconnected in vCenter ui but up at hardware level.

Products

• VMware vSphere ESXi

Issue/Introduction

The status of vmnic is showing as down in vcenter but it is up at hardware end.

 

Environment

VMware vSphere ESXi
VMware vCenter Server

Cause

The link status of vmnic shows down in esxi host ssh.

To check the status of the vmnic from the ESXi host, follow the steps below

• Login to the ESXi host as user root via putty/ssh
• Run the command esxcli network nic list or esxcfg-nics -l

Sample output of the command :-

Name     PCI Device    Driver  Admin Status  Link Status   Speed  Duplex  MAC Address         MTU  Description
-------  ------------  ------  ------------  -----------  ------  ------  -----------------  ----  -----------
vmnic0   0000:01:00.0  ixgben  Up            Down             1000  Full    ec:f4:bb:##:##:##  1500  Intel(R) Ethernet Controller X540-AT2
vmnic1   0000:01:00.1  ixgben  Up            Up             1000  Full    ec:f4:bb:##:##:##  1500  Intel(R) Ethernet Controller X540-AT2

Resolution

The "Admin Status" is the only option that can be managed/modified via ESXi commands.

The "Link Status" column specifies the status of the link between the physical network adapter vmnic# and the physical switch port.

Engage physical switch/network team to check the status of switchport where vmnic is connected at physical switch level.

For more information on troubleshooting link DOWN issues refer - https://knowledge.broadcom.com/external/article/318898