We are using the Cisco ASA and using Exchange server. Currently our MX record points to another server that forwards mail to the inside Exchange server. What I want to do is make that when mail is sent out from Exchange that the ASA uses the same IP as what's on the MX record instead of the firewall IP. This is to make sure that any email servers that do reverse MX lookups will accept our mail properly. How would I best accomplish this via NAT - would I make a global pool for the outside IP? I though a static one to one would work but I'm not sure that's correct. I get a little confused when talkinig about Dynamic NAT since I thought Dynamic was one to many and I would think a NAT from the Exchange server to an outside IP would be one to one? I'm probably confusing myself the more I type - any suggestions greatly appreciated!!