NAT and Reverse DNS Name check

This will probably be off the beaten path a bit, I have a SOHO network with a single gateway computer to interface with the internet. This gateway computer handles a number of external IP addresses and traffic on each which is routed, using NAT, to a different computer on my internal network. One of these internal computers is running the Axigen email server. I have been unable to figure out how to activate the DNS check to “Reject message if the originating IP does not match the HELO/EHELO declaration” It appears, to my untrained eyes, that the NAT translation is confusing the Axigen email server and when I activate this check all emails sent to it are rejected. Is there any way to do this check when all the IP traffic to the Axigen email server has been NAT’ted?

All my computers are running Linux, OpenSuSE Leap 15.1. Thanks in advance for any advice/help.


First please sure that DNS servers that defined in DNR Service working correctly then please check connections reaches to Axigen with which IP. (Maybe inbound connections reaches with internal IP address of your gateway)
you can see inbound connections in logs : [axigen/working/directory]/log/everything.txt