vSwitch port group that is VLAN tagged the same as Native VLAN is not passing traffic through the network

Products

• VMware vSphere ESXi

Issue/Introduction

- You have VLAN tagging configured on a port group attached to the ESXi host.

- The physical switch port that connects to the Host uplinks have the following (example - may differ per switch) configuration and the VLAN tagged traffic is not passing through:

switchport mode trunk
switchport trunk native vlan X

- The port group is tagging VLAN X on that network, which is a Native VLAN

Environment

VMware vSphere ESXi

 

Cause

This would be expected behavior, as the physical switch does not VLAN tag the out going packets toward ESX NICs if the VLAN ID that is used on the vSwitch port group is the same as the Native VLAN.  The vSwitch drops any packet that is not tagged for it, causing the connection to fail.

NOTE: It is common for the physical switch to have VLAN 1 as the Native VLAN by default.

Resolution

To resolve this issue:

- Remove the VLAN ID on the ESXi's vSwitch port group or change the VLAN tagging to something other than the Native VLAN

 

Additional Information

Reference KB: Configuration of virtual switch VLAN tagging (VST Mode)