I had a quick look through the articles in the link you provided, but nothing seemed obvious so far. I will spend more time later today browsing through them but all I want to do is have two mail servers on the inside network with IMAP access. I currently have one mail server with single public IP assigned to ASA. Since BT sells these in packs of 5 with 3 additional IPs, I got confused. Can anyone share the config for such setup?
Ok , I will demonstrate with an imaginary scenario here :
--- ASA -- Two internal email servers
1. Say you want to give these servers imap access .
2. Let us assume that the internal ip`s of the servers are 192.168.1.10 and 192.168.1.11 and the outside public ip`s are x.x.x.x
and y.y.y.y respectively .
Here is what you need : to redirect traffic on tcp imap port on address x.x.x.x and y.y.y.y to your internal mail servers :