Greetings Everyone. Here's my configuration (then I'll get to the problem). Hardware: Quad Core Xeon + 8GB Ram + 500GB Raid 5 Software: CentOS 5.4 (Updated regularly) + Plesk 9.2.2 Unlimited + Atomic Secured Linux + eliminated postfix for Qmail. 8 IP addresses Hosting ~250 simple sites + ~125 e-mail accounts. My problem as stated in the title is that I haven't figured out how to configure reverse DNS across multiple domains on shared IP addresses. for example: IP address 1 hosts the domains: example.com with 3 e-mail accounts, + example2.com with 4 e-mail accounts. IP address 2 hosts the domains: example3.com with 10 e-mail accounts + example 4 with 15 e-mail accounts. Using MXtoolbox.com, everything checks out fine except for the warning: "Warning - Reverse DNS does not match SMTP Banner" Obviously the Plesk server has a name, and that's what is showing up in the HELO/SMTP banner reply. Normally, since the server has never been on a blacklist of any kind, this has never presented a problem. Unfortunately, companies like AOL, Yahoo, and Bellsouth.net are now checking the reverse DNS and SMTP banner before allowing the mail to be delivered. If one of my clients sends an e-mail to someone at bellsouth.net, bellsouth is rejecting the e-mail because the reverse DNS and SMTP banner do not match. Is there a way to add something into the DNS settings for each domain in order to get this to display the correct SMTP banner? Will I have to configure an individual qmail process for every domain on the server? Normally, I would tell these clients to just go get a gmail account and use that, but they really want e-mail at their domain.