iPerf not working between the ESXi Hosts on a vMotion TCP/IP Stack : "iperf3: error – unable to start listener for connections: Cannot assign requested address.

Products

• VMware vSphere ESXi

Issue/Introduction

• Trying to run iPerf between the  vMotion kernel Interface between 2 ESXi hosts fails.
• The vMotion kernel is using vmotion TCP/IP Stack instead of defaultTcpipStack.



• [root@###:/usr/lib/vmware/vsan/bin] ./iperf3 -s -B vmotion_vmk_IP
  
  iperf3: error - unable to start listener for connections: Cannot assign requested address
  
  iperf3: exiting

Environment

VMware vSphere ESXi

Cause

iPerf supports binding only to interfaces associated with the defaultTcpipStack,  Other NetStack like vmotion and custom stacks are not supported. 

Resolution

Please check and confirm if the Source and Destination vmkernel/network interfaces are on defaultTcpipStack.

Additional Information

To identify the NetStack from vCenter:



From ESXi Host you can also verify by SSH'ng and running the below command:-

esxcfg-vmknic -l