Message Rejection

Why Are Messages Rejected?

The UBC mail relays will immediately reject messages sent to and from the UBC campus that:

  • are on the Sophos/Cisco IP Block List - determines if the sender's IP has been identified as a known spammer
  • have a high spam probability - these messages are guaranteed spam.
  • appear to be phishing - a practice where an email message uses psychological techniques and social engineering to collect personal information such as usernames and passwords.
  • contain a virus.
  • contain a suspicious file type - more information can be found here.
  • exhibit irregularities during the message transfer process - for instance, invalid SMTP commands are issued.
  • originate from a compromised mailbox that is sending out spam.

In addition to the rejected messages above, the UBC mail relays tag messages that have a 'medium' spam probability and prepend warning text [Potential SPAM] to the subject line; in addition, a warning banner is inserted at the top of the message advising the user to be cautious of the message contents. Users can then use the header tag to filter these messages to a suspected junk mail folder within their email application (i.e Outlook). Instructions on how to set this up can be found here.

For more information on spam and Phishing, refer to Wikipedia:

How Message Rejection Works

If any of the above criteria are met then the message is discarded with a notification back to the sender, pointing them to this page.
Messages tagged with a 'medium' spam probability will still be delivered but additional headers are added so that email applicants can filter these out if desired.

What To Do If Your Message Has Been Rejected

Sophos/Cisco IP Block List

If your mail server's IP address is on the Sophos/Cisco IP Block Lists, it is likely that delivery to a lot of other mail servers around the world is also affected. It is important to take the necessary steps to remove your mail server from the Sophos/Cisco IP Block Lists as soon as possible.

Since UBC does not manage the Sophos/Cisco IP Block Lists, you will need to visit the Sophos and Cisco websites and follow instructions there on how to remove your mail server's IP address from their lists.

  • Contact the Administrator of your email server for assistance with removing your email server from the IP Block Lists.
  • Email Administrators should go to: http://www.sophos.com/security/ip-lookup/ and https://www.senderbase.org/support to provide the IP address listed in your rejected message.
  • If your mail server's IP is found on one of the SophosLabs or Cisco SenderBase lists, refer to the instructions on their website to remove your mail server from the SophosLabs or Cisco SenderBase block lists.

High Spam Probability Score or Phishing

If you have sent a message that has been rejected, please review its content - it most likely contains text that strongly matches the pattern of a spam or phishing message.

Before you resend your message, review it with the following practices in mind. But please note that these are generally accepted practices, and that adhering to them would not allow spammers to bypass the spam filters.

  • Ensure your message contains an appropriate subject line – avoid generic subjects like, "Hi there"
  • Remove references to prizes, degrees, working from home, surveys and other marketing language
  • Include the recipient's address in the message's To field
  • Do not link to remotely stored images
  • Make sure that your message does not contain links to websites associated with phishing
  • Try to avoid masking the true website address within a link in the email message.
  • Avoid using coercive language

Invalid HELO or EHLO Command

If your message has been rejected with an "Helo command rejected: Invalid name" error, it means that your mail host has been improperly configured. Internet standards require connecting mail hosts to issue a "HELO <host name>" statement upon connection. Please contact your Internet Service Provider to remedy this situation. Alternatively, you can configure your mail software to use an alternate outgoing mail server if one is available.

Suspicious Attachment

The UBC mail relays block a number of attachment types including all executables. More information on this can be found here.
This page includes instructions on how to embed these attachments within a password protected zip file.

Credit Card Data

Anyone attempting to send credit card information to a UBC email address will receive an automated message indicating that transmission of this information is not permitted under UBC policy. The email will still be delivered to the intended recipient, however, in the future this type of email may be blocked completely. If you send a message that is incorrectly tagged as containing credit card data, you can send the message using a password protected zip file as a workaround. Instructions for this can be found here.