ARP Table reporting routes for entire /22 subnet
So I'm using IP passthrough on my AT&T gateway device (an ARRIS NVG589) so that my pfSense firewall/router's WAN interface is getting the public dynamic IPv4 address. I'm also using the Cascaded Router feature for an /8 block of static IPv4 addresses.
While I was troubleshooting something else, I found that the pfSense ARP Table has a huge amount of entries corresponding to each IP address on the /22 subnet of my dynamic IPv4 address. The MAC address for the routes is the address of the gateway device.
Since I would rather the WAN interface have this IP address, is there any way to prevent the ARP Table from enumerating all these entries?