I have a new postfix server up and running with a hostname of serverx.mydomain.com . Works fine. I also want to map smtp.mydomain.com and mail.mydomain.com to be this same server. I update my dns boxes to point to this servers ip address for those names, and customers cannot send mail to it. If they put either serverx.mydomain.com or the server's ip address in their email client, it works. Where in postfix do I specify additional names to listen to? Also, this server needs to relay my customers domains as well. If their email is email@example.com, the server works. If they are at firstname.lastname@example.org it refuses to send the message out. Is there a file where I need to list all of my customers domains in? Thanks for the help!!