Can PFsense do this with a single firewall?
This is my following setup(please see attached). I've been running this the last few years and it works very well.
It allows me to run the same webserver off two public IP's from different providers. I use DNS to load balance (round robin) between the two IP's and remove one if a connection dies.
I would like to consolidate my two Monowall firewall's into a single one with PFsense. Would this be possible?
Yes, pfSense can do this. Your server even only needs one nic then as for both connections the pfSense is the gateway (pfsense will take care of the forwarding to/from the right wan). I have this setup at the office with 2 mx entries for our mailserver so it can be reached via both wans in case one of the WANs fails. You also might be interested in the upcoming DNS package (will be available once 1.2 release hits the road) which can do this kind of balancing/failover too.
Works like a charm :) Thanks for your help!!