Use the Traffic Loopback tab in the Troubleshooting page to enable the interface loopback configuration.
To enable the interface loopback functionality:
In the Web UI, navigate to Troubleshooting > Traffic Loopback.
In the Traffic Loopback Configuration section, set the Enable Traffic loopback mode option to On.
Select the Interface Loopback option.
Select the applicable port pairs.
Click Apply.