Inbound Traffic 2 Gateways different public IPs one Interface

[BJ55463]

Hello,

on my wan interface theer are two gateways for failover. I also use two pfsense firewalls in ha. Both gateways use diffrent isp so there are diffrent ips. Both gateways forward all traffic to the carp ip on the wan interface. Thats works very well. But I have one problem. GW1 is the default gw. GW2 is used only if GW1 is offline. If traffic comes from GW2 while GW1 is active, i cannot make a connection. For example: Inbound mails should be send to puplic IP from GW1 or public IP from GW2. This works because the mailserver test the other connection if one fails. But only one connection works (the connection where the gw is actually the default gw for the pfsense box). So is it possible to tell pfsense to use the not default gw for answers if the incomming connection came from this gw?

Best regards,

Alexander