Hi I have an issue with email in a fresh install of CentOS 6. The server is in a internal LAN with a non-routable private IP. I opened port 25 and 110 using SSH in iptables. The weird part is that I can send email using the mail command in SSH to only some email addresses. I was successful at sending email to a Gmail address as well, but it went into the bulk folder. Here is a copy of the headers in an internal email I received... Return-path: <seXXXXXX @ host-server16.com> Envelope-to: rXXXXX @ maXXXXXXXXXXXX.com Delivery-date: Fri, 25 Nov 2011 03:50:35 -0600 Received: from [X8.203.74.XXX] (port=44105 helo=host-server16.com) by gator1501.hostgator.com with esmtp (Exim 4.69) (envelope-from <seXXXXXXXXXX @ host-server16.com>) id 1RTsQV-00056y-DZ for reXXXX @ maXXX.com; Fri, 25 Nov 2011 03:50:35 -0600 Received: by host-server16.com (Postfix, from userid 500) id 5E41A102012; Fri, 25 Nov 2011 04:50:35 -0500 (EST) Date: Fri, 25 Nov 2011 04:50:35 -0500 To: reXXXXXXX @ maiXXXXXXXX.com Subject: test2 User-Agent: Heirloom mailx 12.4 7/29/08 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-Id: <20111125095035.5E41A102012 @ host-server16.com> From: seXXXXX @ host-server16.com (seXXXXXXX) I also changed the host file from localhost to host-server16.com because it was stating in the email headers "localhost-server name" I install Active Campaign in the server but it can not send or receive, even when I tell it to use an external SMTP account. I did made a testing.php page and uploaded it to /var/www/html... when I test it, using my internal IP, I do get a php page stating that PHP 5.3.2 is installed. What I would like to do is have my internal hosted server relay using SMTP. So my domain host-server16.com is hosted in a shared hosting environment but I can relay using SMTP and dynamic DNS to reach this server. I came across this link in order to relay using Postfix, but I have to fix the email issue first... http://howtoforge.com/postfix_relayi...her_mailserver I am also a little confused about Postfix and Heirloom mailx. In the header states both MTAs, which one am I using? Thanks for your help.