2 pfsense on the same subnet - 1 being gateway for the other
I have 2 fiber WAN connections each connected to one pfsense box.
I would like to route part of one box traffic through the other box WAN link.
I currently have the 2 boxes on the same LAN subnet /24 with IPs xxx.1/24 and xxx.2/24
Is it completely wrong ? or could I use the xxx.2/24 pfsense as gateway for the xxx.1/24 for some specific destinations (for example).
The 2 WAN links are not 100% identical, for ex. 1 has a dynamic IP while the other as a fixed IP. That's why I'm interested in driving which trafic goes which way.
Is there a specific reason for using 2 separate PfSense instances?
A single instance with 2 WAN interfaces would have no problem routing the way you want it to.
You may be able to do what you are seeking with a static route, but I have never tried what you are planning myself.