Recently there have been a number of questions about what causes email to be quarantined and why sent messages are scanned. Email messages are scanned when they are sent from our Exchange system (the email for faculty and staff) to a non-ashland.edu email address and when a message is received from an account outside our Exchange system. Every day a Quarantine Report is sent to each email account from the anti-spam server. This report lists all emails that have been quarantined along with a general description for the reason and a link to delete or release the messages. In 2008 student email accounts were moved from the old GroupWise email system to a Gmail hosted account.
Why do we scan email that is being sent? To protect the reputation of our email servers. Email servers have their own reputation and the Ashland University email server “talks” to thousands of other email servers on the Internet. If our email server develops a poor reputation score because we are sending spam, high volume, or incorrectly addressed emails, other email servers will no longer trust the email we send. The term is “blacklisting” and there are servers dedicated to providing this list to other email servers. Our email server has been blacklisted in the past. This happened because an email account was accessed by an unauthorized person or software and used to send spam. Being blacklisted is crippling to the business functions of the university. Email servers usually do not send a failure notice so the sender does not know that the message did not reach its destination. Removing an email server from the blacklist is a time consuming and labor intensive process, and it can take several days for mail to start flowing normally.
What causes a message to be blocked? Messages are blocked due to size, attachment type, virus or other potentially harmful content, grammar, keyword combinations, blocked sender lists and heuristic or speculative filtering. For example, a message containing the phrase “mortgage” by itself does not necessarily set off a red flag. It could be a reminder email from the bank that the mortgage payment is due. But the word “mortgage”, combined with “bad credit”, “no problem” and “apply online” will be considered spam. Our anti-spam server has many custom rules that have been created due complaints of messages that slipped past the default filters. Knowing what these rules are will help you to better craft your message to prevent it from being quarantined. A list of our custom rules, blocked attachment types and a long explanation of heuristic filtering can be viewed at here.