I work as a Systems Administrator for a school. We have our own Mail Server that runs on Mdaemon. I have my network running on local IP (192.168.x.x). I have a cisco router that has a real ip and a local ip. My mail server is running on local IP. I have defined NAT (in fact PAT) rules to re-direct trafffic from router to mail server and vice versa. The problem is that some of the domains (like AOL) traces the source of the email and get my local IP as source IP thus deny or reject the email generated from our mail server.
I want to switch my mail server to a real IP. What is the best way to accomplish this? I do have available real IPs. My concerns are:
3. Simplicity of the solution
Will I have to make my mail server a multihome system (with two NICs, one facing the LAN and other facing the WAN)?
I will really appreciate your help. Thanks.