VM connectivity issues observed over a newly created HCX Layer 2 extended network

Products

• VMware HCX

Issue/Introduction

• A network has been L2 extended through HCX between the Primary SDDC and Secondary SDDC. However, none of the VMs on the newly extended network are reachable from the source SDDC.
  
  
• Packet captures taken on the source VM’s switch port, NE_I1 (source Network Extension appliance), and NE_R1 (target Network Extension appliance) MAC learning switch ports show that ARP requests are being sent but no replies are received.
  
  
  
  
  For packet captures on ESXi using pktcap-uw, please refer :
  
  Packet Captures in ESXi using tcpdump-uw
  
  Troubleshooting NSX using Packet Captures
  
  Performing Targeted Packet Captures on HCX Network Extension Switchports
  
  
• Additionally, the packet capture on the destination VM’s switch port shows no ARP requests being received.

Environment

HCX 4.11.x

Cause

This issue can occur if MAC Learning is disabled in the NSX MAC Discovery Profile.

Resolution

Ensure that MAC Learning is enabled in the NSX MAC Discovery Profile on NSX.

Note: If NSX is also deployed on the source environment, ensure that MAC Learning is enabled there as well.

Additional Information

Understanding MAC Discovery Segment Profile