Intermittent VM connectivity in NSX when traversing an L2VPN

Products

• VMware NSX

Issue/Introduction

• Traffic fails going over the L2VPN from time to time.
• If a continuous ping is instigated, the connection returns.
• The host where the the L2VPN resides is configured using promiscuous mode Configure an NSX Edge Uplink Port in ESXi

Environment

VMware NSX

Cause

When configuring an L2VPN and using promiscuous mode, the host where the autonomous edge resides must have 'esxcli system settings advanced set -o /Net/ReversePathFwdCheckPromisc -i 1' set to avoid looping packets.

When setting this option, promiscuous mode must then be flipped from Accept to Reject and back to Accept on the portgroup, for the setting to take affect.

Resolution

Follow the steps at Configure an NSX Edge Uplink Port in ESXi to ensure the settings are correct and that promiscuous mode was flipped from Accept to Reject and back to Accept on the portgroup.

Additional Information

Duplicate Multicast or Broadcast Packets are Received by a Virtual Machine When the Interface is Operating in Promiscuous Mode

L2 loop causes invalid MAC learning on NSX-T Edge Node when NPAR TX switching and L2VPN is enabled