Our email is being rejected by certain email servers.  (comcast is one)  I have done reverse dns and have checked all the white list.  Can you tell what is wrong by seeing this header?
Received: (qmail 23883 invoked from network); 6 May 2008 16:34:23 -0000
Received: from unknown (HELO pre-smtp30-02.prod.mesa1.secureserver.net) ([10.0.19.130])
          (envelope-sender <SteveMc@swiftprint.com>)
          by smtp12-01.prod.mesa1.secureserver.net (qmail-1.03) with SMTP
          for <nickw@jerichomgt.com>; 6 May 2008 16:34:23 -0000
Received: (qmail 10358 invoked from network); 6 May 2008 16:34:22 -0000
Received: from mail.swiftprint.com ([12.18.228.213])
          (envelope-sender <SteveMc@swiftprint.com>)
          by pre-smtp30-02.prod.mesa1.secureserver.net (qmail-ldap-1.03) with SMTP
          for <nickw@jerichomgt.com>; 6 May 2008 16:34:22 -0000
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain;
      charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
Subject: Email Server Test - Online SMTP diagnostics tool
X-MimeOLE: Produced By Microsoft Exchange V6.5.7235.2
Date: Tue, 6 May 2008 11:34:18 -0500
Message-ID: <46DD188E47712B4BB0D289AE01E598CF102E52@swiftmail.SwiftPrint.local>
X-MS-Has-Attach:
X-MS-TNEF-Correlator:
Thread-Topic: Email Server Test - Online SMTP diagnostics tool
Thread-Index: Acivlwf/OugnuYFOR36vGlIpMOcPsA==
From: "Steve McKinney" <SteveMc@swiftprint.com>
To: "Nick Weyer" <nickw@jerichomgt.com>
X-Nonspam: Statistical 62%