After looking for suitable hardware for a pfSense box I ended up buying a the pfSense SG-2220.
On arrival I just had to swap the US power cable to an AUS one.
My network setup was NBN Cable modem to Huawei HG659 to Asus router.
The plan was to put the pfSense box between the Huawei and Asus, which it is now.
Initial setup of the pfSense box via laptop and LAN port, just use the setup program/wizard, dhcpd on for the LAN. The WAN port should dhcp client its address. cool.
So the Asus router will just become a switch and WiFi AP for this setup. Login and turn off dhcp. Change the WAN port cable to a switch port.
Insert the pfSense box, and turn on. It will take a while to update and stuff so don't go crazy and rage quit. oh and don't have a layer 1 problem like me and have the LAN and WAN cables in the wrong ports. head wall. don't ask.
Once setup login to the pfSense box and look at all the pretty firewall info/graphs and logs. Sweeeeet bro.
What problems did I have:
layer 1 LAN WAN cables on pfSense box.
Normal in a rush with network gear, hurry up and wait. expect 20 min on first internet connection.
Asus not changing as expected. i.e. the WAN port has the IP not the router device itself.
And the mother of all shit storms was my windows 10 box loosing USB ports after 4min. hard reboot, 4min USB fail. disconnect pfSense WAN cable and it came good after reboot. reconnect pfSense WAN cable and still good.
I hope this helps someone out there.
Cheers
Boo