You can use the automated traceflow tool or manually trace the packets to troubleshoot packet loss.

To run the traceflow tool, from the NSX Manager GUI, navigate to Tools > Traceflow. For more information, see the NSX-T Administration Guide.

Procedure

To manually trace the packets,

On ESXi, run net-stats -l to get the switchport ID of the VIFs. If the source and destination VIFs are on the same hypervisor, run the following commands:

pktcap-uw --switchport <src-switch-port-ID> --dir=0
pktcap-uw --switchport <dst-switch-port-ID> --dir=1

If the source and destination VIFs are on different hypervisors, on the hypervisor hosting the source VIF, run the following commands:

pktcap-uw --switchport <src-switch-port-ID> --dir=0
pktcap-uw --uplink <uplink-name> --dir=1

On the hypervisor hosting the destination VIF, run the following commands:

pktcap-uw --uplink <uplink-name> --dir=0
pktcap-uw --switchport <dest-switch-port-ID> --dir=1

On KVM, if the source and destination VIFs are on the same hypervisor, run the following command:

ovs-dpctl dump-flows