@Cyberben:
I can use my browser to get to the machine through WAN/dhcp.
When you setup a router / firewall device, you hook yourself up for initial setup using a local serial port (could be a serial over USB), or a dedicated NIC, or, by default, the future LAN NIC.
Never ever the future WAN port.
That goes for pfSense and any other device on this planet.
Knowing this, you will find this :
@Cyberben:
I simply tell the machine there is a LAN NIC I loose connectivity to WebGUI.
… normal.