Rechner 1 (OPNSense FW) <<-->> 10 GBit Switch (Cisco SG350X) <<-->> Rechner 2 (Proxmox)
ifconfig ethX mtu 9000 up
Du solltest immer den Traffic DURCH die Firewall messen, also hinter die OPNsense ein Gerät mit 10G was den Traffic misst.
"iperf ... is NOT a suitable way of testing firewall throughput, as there is a significant difference between performance of traffic initiated or terminated on the firewall and traffic traversing the firewall."