IPS/IDS For 1-to-1 NAT Firewall Setup?

Hi Guys,

We're evaluating ClearOS 7.2 Business which will be used in Gateway Mode to protect traffic originating from servers behind ClearOS. We are using 1-to-1 NAT Firewall setup to map a public IP to private IP behind ClearOS. I wanted to know if IPS / IDS and antimalware / antivirus will still be able to protect traffic originating from servers behind ClearOS with 1-to-1 NAT firewall setup. I have read in one of the pst that this may not work as expected as traffic will not be scanned with IPS / IDS and for virus / malware if we are using 1-to-1 NAT firewall (which assigns a virtual IP to external eth).

Can some experts provide me with your inputs here and confirm that traffic will still be scanned / protected with 1-to-1 NAT firewall setup?

Many Thanks
Ruchir