How does SpamAssassin mark non-spam messages at Progressive Networks?
In addition to marking every spam message, SpamAssassin also add information to the headers to non-spam messages as well. That information will look something like this: X-Spam-Flag: No, 0.612 out of 5. Tests: SARE_HTML_INV_CHARSET Again, the X-Spam-Flag is present and contains three sets of information. The first is a boolean value of ‘No’ telling you the message is not spam, and the second is the score it assigned to the message out of the default threshold. In this case, the message got a score of 0.612 out of 5, which isn’t high enough to make it a spam message. Finally, we also include the tests which returned a positive match for typical spam characteristics.
