Looking to make the WAN port a switch port

Hi Folks,
I recently purchased a netgate SG-1100 pfsense firewall appliance. This is physical layout I have:

OpenWrt Router (LAN on 4 x switch ports and 2 x WiFi (2.4/5GHz) - Archer 2600) WAN port on Router >>>>>>>>>>> LAN on pfsense SG-1100 , WAN on pfsense SG-1100 >>>>>>>>>>> Surfboard Modem >>>>>>>>>> Coax to Xfinity ISP

I want to do away with the firewall on OpenWrt and make the WAN port a LAN port. Does anyone know how to do this, so I can do away with double-NAT on my pfsense firewall?

I'm running 18.0.2 on my router at present. Thanks for the help.


I'd personally go fot what @lleachii suggested as it does only the nicessary changes, making it easy to change the port back to WAN if and when you need.

If, after sometime, you decide that you are unlikely to need the WAN in the future, you could go ahead and delete its VLAN and interface I suggested by other people in the same topic