As indicated, I am having to retrace my steps to figure out why I can't get my Postfix installation running properly. I believe (being very new to this) that my DNS connectiviety is the issue. My server (192.168.XX.XX) is behind a firewall appliance that is assigned the IP 74.XX.XX.XX. I apologize for asking very basic questions, but I need to ensure that I am not misunderstanding so that I can get this right. 1): the perfect setup example shows a mapping of an "Internal IP" to its related FQDN. In my case, my "EXTERNAL IP" is mapped to my FQDN. Is this correct? 2) Does the DNS port (53) need to be forwarded in the firewall appliance (mine is)? 3) Before even starting up POSTFIX I run IFCONFIG and get inet = 192.168.XX.XX; If I run NSLOOKUP mail.xxx.com, I get my server (mail.xxx.com) and the EXTERNAL IP (74.xx.xx.xx). Is this correct? Again, I appreciate any help in stepping through this. My frustration is growing, but I am endeavoring to stay patient!