Network Configuration

Ok I am deciding how I should setup my email server to access the internet.

The first way would be to give it an public ip address and put it on the DMZ and setup access rules on the DMZ, I can apply NAT on the DMZ if necessary

The second way would be to use port forwarding from the firewall so I can give the email server a private ip address but specify on my firewall that this public ip address conrresponds to this private ip address

Iam still deciding if you can give me any pro’s and cons’s on either solution I would appreciate it. I am using Domino for email