OPNsense replasing sender's IP address in header

[it.dep]

Hi guys!

The scheme of the mail server:
Internet -> Gateway 192.168.2.1 -> OPNsense Haproxy 192.168.2.8 -> Exchange2019 192.168.2.5

According to this scheme, in all incoming letters to Exchange, the IP address of the sender is replaced with the IP address 192.168.2.8 (OPNsense Haproxy).

In the screenshots it is clearly visible: True IP - configuration without OPNsense, False IP - configuration with OPNsense.

True IP


False IP


We use spam filter ORF Fusion. For spam filter to work correctly, it is necessary that all incoming messages are with the sender's IP addresses, and not replaced by local IP OPNsense.

Is it possible to fix it? What can we do in this situatuation?