University of Manitoba's Bulk Email Filter - DCC

The University of Manitoba's email system rejects messages that have been mailed in bulk because these messages are usually spam. We return them to the senders with an explanation of why they have been rejected. We also keep a list for 14 days of messages sent to you that have been rejected.

  • Please check this list periodically for valid mail and add it to our whitelist so that future messages from the same sender are not rejected.
  • We recommend that you subscribe to a weekly mailout of your bulk mail summary.
  • Receive your weekly summary by email
    You may want to subscribe to this mailout service instead of having to remember to check the DCC web page. Use your UMnetID to subscribe.  (Your Firstname_Lastname alias will not work.)  You will receive an email request to confirm your subscription.

    After your confirmation is received, each Monday morning you will be sent a summary of your identified spam bulk mail of the previous 14 days.

    You can unsubscribe at any time using the same web page.

    Check and whitelist your bulk mail on the DCC web page
    Login to this page with your UMnetID username and password. (Your Firstname_Lastname alias will not work.)

    You will see a list of the filtered mail that was addressed either to your Firstname_Lastname alias or to your UMnetID at address.  

    Look for legitimate mail amongst your spam.

    Click on View beside a message that appears legitimate in the bulk mail summary to examine it further. If it is indeed not spam, you can click on Nominate to add that sender to the University-wide whitelist. Once the sender is white listed by anyone at UofM, future messages from that source will not show up in the bulk mail list.

    Contact the IST Help & Solutions Centre if you need help.

    Not all bulk mail is spam.

    Some bulk mail is legitimate, e.g. subscriptions, conference info, product update announcements, etc. Check your DCC bulk mail summaries for legitimate email, especially after you give out your email address at an event or to any group or organization.

    When does DCC consider a message bulk mail?

    A message is considered bulk mail when over 100 copies, as seen by DCC sites around the world, contain substantially identical content.  A message can be rejected even when only one copy arrives at the UofM.  DCC compares only the body of a message when checking for bulk mail, not the header or attachments.

    My requests for Confirmation of Receipt are caught as spam!


    Solution: Whitelist it. Receipt confirmations are identical to each other and are therefore bulk mail. We have whitelisted most variants, but each new mail program version may have a different format and so new ones will be caught as spam until one UofM user whitelists one example. Then all the rest from that mail program version will get through. One person's whitelisting helps everybody else. Please help.

    Why was that message blocked... It isn't spam!

    1.  DCC does not look at attachments when checking for bulk mail.

  • Example: The sender sent you an attachment with no text in the body of the message. That makes it identical to hundreds of other messages received any week, just like spam.
  • Example: The sender sent you an attachment with just their signature in the body of the message. They've sent one hundred other such messages to UofM recently.

    Solution: Ask your correspondents to include an individualized short message describing the attachment. 
  • 2.  If your email message contains no English, Spanish, or Polish words, it may get classified as bulk mail. 

    Why isn't my missing mail in the bulk mail summary?

    If you are sure the email address was correct, allow enough time for delivery delays and the summary update; then check again. The bulk mail summary is updated only twice an hour. 

    Do I get the message I whitelist?

  • Not that particular message, but all subsequent messages from the same sender will get through. The original message was already returned to the sender with a delivery rejection notice.
  • However, the first 32K (about 400 lines) of each message is kept in the bulk mail log on the summary web page so you can copy and paste it to a file. If there was an attachment, you will need to ask the sender to resend the original message.
  • Each day's rejected messages can be viewed for 14 days only before they are discarded.
  • How does the whitelist work?

  • There is one whitelist for all mail.
  • The addresses shown in the "From:" and the "Return-Path" fields of a message are added to the whitelist. Messages from these exact addresses will be accepted in future.
  • Unfortunately the sender's address may vary in the case of mail from some large vendor mailing lists. This makes it necessary to whitelist more than one message from one organization or company.
  • Who can whitelist a message?

  • any UofM recipient of one of the trapped messages
  • only after at least one message has been trapped in the bulk mail summary
  • How do I know if an email has already been whitelisted?

    If it has already been whitelisted and you nominate it, DCC will tell you.  There is no harm in making duplicate nominations.

    What if someone whitelists mail that shouldn't be?

    The nominator's address is logged. Accidental nomination can be undone by the postmaster. Unintended nomination of spam is unlikely since spam is rarely sent from the same address twice.

    For more information, visit the DCC product site.

    Last updated: June 5, 2006