Exchange: Outlook and OWA attachment issues

Outlook client does not display attachments

There are a number of reasons why this might be the case.

• See http://knicksmith.blogspot.com/2007/03/exchange-2007-and-outlook-2003-where.html. An issue was resolved by Microsoft in Exchange 2003 Service Pack 1 where Exchange 2007 was incorrectly causing Outlook 2003 to hide inline attachments. Even though you could not see the attachment, if you flagged the email, or clicked forward on the email, the attachment would appear correctly. Also if you selected Save attachments from the file menu, it would still save the attachments. OWA is not affected by this.
• See http://social.technet.microsoft.com/Forums/en-US/exchangesvrclients/thread/478c326b-486b-461c-9141-dd544b245c75. Symptoms: You can see the attachment in OWA but not in any of the current versions of Outlook. Outlook blocks the attachment completely and there is no way to retrieve it through this interface. This is also more likely to happen when an inhouse application has been programmed to send email with attachments. if the MIME is formatted incorrectly then Outlook will not display it. RFC 2387 describes the intended use of multipart/related:
  http://www.ietf.org/rfc/rfc2387.txt:
  "The Multipart/Related media type is intended for compound objects consisting of several inter-related body parts. For a Multipart/Related object, proper display cannot be achieved by individually displaying the constituent body parts."
  Steps to resolve this issue involve changing the MIME header to Multipart/Mixed instead of Multipart/Related. Multipart/Related will cause the attachment to be considered inline by Outlook. As there is no reference to the attachment in the body, it will then effectively be ignored. OWA has more smarts and is able to determine if an attachment is really inline or not. If it finds no reference to the attachment in the body of the email then it displays the attachment as a separate entity.

SMTP and Internet mail toubleshooting

Issues with Internet mail delivery

If your mail is getting rejected:

• Check your mail domain is configured correctly in external DNS at http://www.intodns.com/
• Check that your mail domain has not been blacklisted at http://www.mxtoolbox.com/
• Check that your domain has a PTR record in public DNS
• Check that your domain has an SPF record. Absense of this record will make other mail systems more likely to reject mail or classify it as spam. See http://www.openspf.org/Why for more information or to test SPF.

If mail is getting rejected by hotmail, check http://postmaster.live.com/.

Issues with scanning to email

If you are scanning mail to your inbox but it is not arriving, or other email is not arriving consistently:

• Check if other people are able to receive mail from the scanner
• Find the IP address and name of the scanner, and try to manage it remotely through HTTP or HTTPS
• Check junk email folder. If they are going into junk email, add the scanner "from" address to the safe senders list on the Outlook client.

Issue sending to Exchange 2007 distribution lists from external

If you are sending to a distribution list that is hosted in Exchange and you sending from external, you may receive the following very helpful error messages: -

• Your message wasn't delivered because of security policies. Microsoft Exchange will not try to redeliver this message for you. Please provide the following diagnostic text to your system administrator.
• #550 5.7.1 RESOLVER.RST.AuthRequired; authentication required ##rfc822;travnatad@smtpex.toll.com.au

The answer is generally quite simple. An Exchange 2007 distribution list requires senders to be authenticated by default. To disable this, go into the distribution list properties and on the Mail Flow tab, select Message Delivery Restrictions. Uncheck the box that says "Require that all senders are authenticated". Then mail will start to flow.