I can send mail through SMTP using outlook without any problems. The problems come in when sending an automated email through our shopping cart via PHP. Diagnostic-Code: X-Postfix; host relay.verizon.net[126.96.36.199] said: 550 You are not allowed to send mail:sv22pub.verizon.net (in reply to MAIL FROM command) Received: from server.myserver.com (server.myserver.com [127.0.0.1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by www.myserver.com (Postfix) with ESMTP id C869E1CCB96 for <[email protected]>; Sun, 4 Mar 2007 09:01:22 -0500 (EST) Received: (from [email protected]) by server.myserver.com (8.13.1/8.13.1/Submit) id l24E1Mu1009247; Sun, 4 Mar 2007 09:01:22 -0500 I assumed this is because of the server name and attempted to change the name in /etc/hostname and using /bin/hostname -F /etc/hostname. That worked fine until reboot and the it changed back to server.myserver.com. Also, it could have been the (from [email protected]) and that indicates message header problems in PHP. However the header is being set properly in the PHP Script. Any ideas why the server name would change back? Any ideas on an overall fix?