I have 2 1Gbps USB Ethernet dongles on the same PC that are cabled together, and I'd like to ping (and maybe iperf) between them to quickly verify performance. I've assigned them different static addresses on the same subnet, but my pings are handled in the network stack and don't go through the hardware.
How do I force the pings to go out through the hardware then over the wire between the adapters?
Context: I have dozens of 1G USB RJ-45 Ethernet adapters of various ages, and I'm trying to quickly identify the dead and slow ones without putting traffic onto the LAN.
BTW, it's a Win10 PC with WSL Ubuntu 20.04, so any solution that works via either domain is fine with me.
Edit: Both adapters are on USB3 ports.