Spam at CU-Boulder — Marking Potential Spam

Marking Potential Spam

ITS uses an e-mail filtering technology to process incoming e-mail for spam and viruses for the CU-Boulder campus. This system scans incoming messages using an extensive collection of rules to determine the likelihood of each message being spam, then assigns a numeric score to each message.

Current System, IronPort

On September 9 ITS implemented a new e-mail filtering service for the campus. The service is called IronPort. It continues to filter away most spam messages and will tag those that could be spam as "Potential Spam" so that you can keep filtering those messages away from your inbox.

There is a difference though in how spam is judged and scored from the previous system. Messages are given an "SBRS" (SenderBase Reputation) score and an IronPort SPAM Score. For SBRS, the range is from 10 (likely a trustworthy sender) to -10 (apparent spammer). A score of "none" indicates that there was no information about the sender at the time the message was being processed.

For the IronPort SPAM score, the range is 0-100. E-mail scored between 0-49 are considered "clean" and are delivered without alteration. Messages scored between 50-90 are considered "suspect" and are tagged with POTENTIAL-SPAM in the subject line. Messages with a score of above 90 are considered positive SPAM and are not delivered.

Note: SenderBase Reputation scores (SBRS) and the IronPort SPAM scores don't display in message headers.

You can configure your e-mail client's filter to move potential spam to another folder where you can periodically check for false positives and delete the rest.

That way, you decide when to deal with spam, rather than having it interfere with reading your legitimate e-mail.

Previous System, Barracuda

Note: This system was retired on September 9, 2008. The information below is only for reference.

In the previous e-mail filtering system, the higher the number, the more likely a message was spam. Messages that had a score between 4 and 8 were marked as POTENTIAL SPAM, while messages with a score higher than 8 were blocked and never delievered to your e-mail account. If the message was flagged as "Potential Spam," and delivered to your e-mail account, the scoring information appeared in the message header. To learn more about e-mail headers, visit www.colorado.edu/its/email/headers.html.