Spam at CU-Boulder — Understanding E-mail Headers

Understanding E-Mail Headers

The new technology ITS recently began using to process incoming e-mail for spam and viruses, affects the appearance and content of e-mail headers. E-mail headers are the lines at the top of an e-mail message that are used by e-mail servers as messages are delivered. An example of an ITS e-mail header is shown below:

An e-mail header can reveal a lot of information about where a message is delivered from, how it is delivered to you, and the Spam score it has received.

ITS technology scores messages on a spam scale of 0-10. The higher the number, the more likely a message is spam. Messages with a score between 4 and 8 are marked as POTENTIAL SPAM, while messages with a score higher than 8 are blocked and never delievered to your e-mail account. If the message is flagged as "Potential Spam," and delivered to your e-mail account, the scoring information will appear in the message header.

Read through the explanations below for help understanding ITS e-mail headers:

X-Barracuda-Bayes: This is the Bayesian score that was assigned to the message. (See Bayesian analysis defintion)

X-Barracuda-Spam-Score:  This the total spam score that was assigned to the message. (ie, Bayesian + spam score assigned by the different spam tests)

X-Barracuda-Spam-Status: (Yes or No). Whether the message is spam or not.  This also shows the score at which the message is tagged (TAG_LEVEL=4.0), blocked (KILL_LEVEL), and quarantined (QUARANTINED_LEVEL=1000.0) <-- disabled  . This also shows the different spam rules that applied to this message

X-Barracuda-Spam-Report:  This is a breakdown of the scores that were assigned to the message. The left column is the score of the rule that applied. The middle column is the name of the rule that applied, and the right column is a description of the rule. Custome Rule xxxxx are rules that are written and maintained by Barracuda Networks for messages that have certain spam patterns.