Hi, we have Ironport ESA deployed in one-arm mode. all incoming email passes through Ironport before for warding it to our Lutos server. The issue when we set Lutos server to relay outbound emails to Ironport for Security processing then Ironport sends it outbound. Outgoing mail are rejected by Ironport error "Rejected by RAT".
Apologies for the late reply. I was out due to long holidays.
We have set the configuration mentioned above during the initial setup of the ESA. We found out that the issue is with the Notes server smtp connector configuration. The new admin is not so familiar with Notes so until now they are still trying to figure out how it is should be done.
You should go to Mail Flow Policies/Recipient Access Table and add a record four your domain with Default Action Accept. Also should create Relay List and add all your internal mail servers IP to relay list.