Spam at CU-Boulder — Understanding E-mail Headers

Understanding E-Mail Headers

New Ironport Technology Changed Headers

On September 9 ITS implemented a new e-mail filtering service for the campus. To the casual e-mail user the change is largely transparent; suspected messages are still tagged as “Potential Spam.” For those that read headers, or filter e-mail based on header information, this change will be more significant. Note: SenderBase Reputation scores (SRBS) and the IronPort SPAM scores don't display in message headers.

In the header, lines 1-4 are different for CULink customers and Exchange customers. The images below demonstrate that difference.

First four lines of the header for a CULink customer:

First four lines of the header for an Exchange customer:

Remaining header text that is the same for both CULink and Exchange customers:

Previous Barracuda System

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

The technology ITS was using prior to September 9 affected the appearance and content of e-mail headers differently than the new system does. An example of the Barracuda ITS e-mail header is shown below: