Proxy ARP option on USG to work like L3 switch

PeterUK

This was tested on my VPN300 but likely holds true for current models

The following setup works on my XS1930-10

XS1930-10 interface IP 192.168.255.233 / 255.255.255.192

Two clients
IP 192.168.255.193
subnet 255.255.255.255
gateway 192.168.255.233

IP 192.168.255.194
subnet 255.255.255.255
gateway 192.168.255.233

As the subnets of the clients is 255.255.255.255 it can only ARP to the gateway never to each other but due to XS1930-10 when you ping 192.168.255.194 from 192.168.255.193 it works.

on VPN300 with interface general 192.168.255.247 / 255.255.255.192 and proxy ARP 192.168.255.193-192.168.255.194

Two clients
IP 192.168.255.193
subnet 255.255.255.255
gateway 192.168.255.247

IP 192.168.255.194
subnet 255.255.255.255
gateway 192.168.255.247

The clients try to ping each other they go to the VPN300 gateway but the proxy ARP does not work the same way as L3 switch.