Spam Tagging Levels Explained

There are three main numbers associated with spam. The spam engine assigns a probability of an email message being spam, with lower numbers being less likely.

NOTE: small changes make a huge difference. A tag level change from 5 to 5.1 is huge.

The three main levels (tags) are defined below:

Tag Level Any mail with a spam score higher than this will cause a score header to be added to the mail. This is for the use of rules and filters in your mail reader, and it not normally visible to you. You will have to View Headers from your mail reader to see these.
Tag2 Level Any mail with a spam score higher than this will have ***SPAM*** put into the subject. Additionally, it can be automatically moved into the Junk folder before you even see it if you have this option set in the control panel (or RoundCube)
Kill Level Any mail with a spam score higher than this would “normally” be discarded. However, we have decided to set this to go ahead and put it in your Junk folder to ensure you never have e-mail rejected

Notes for power users:

In your mail configuration (either through the Control Panel at or through RoundCube at, you can have any e-mail over Tag2 Level moved to your Junk folder before you even check mail. This is done by going to the Junk setting (Settings | Account | Junk on RoundCube) and placing a check in “Move Spam Emails to Junk directory”. You will then never see spam in your Inbox; it will only go to your Junk folder.

Additionally, many mail readers allow you to create Rules or Filters which can look for the Spam filter header which the spam engine puts in. There are two header tags that are very useful to you (following taken from actual spammy message):

  • X-Spam-Score: 20.81
  • X-Spam-Level: ********************

The above says the spam filter gave this a spam score of 20.81 (it was an ad for Viagra, definitely spam). The second is designed for e-mail rules and filters. It puts one asterisk for each level of the Spam Score (20 in this case). If you want to do something with anything over a score of 7, you would use the rule:

X-Spam-Level: *******
(that is 7 asterisks). Since anything over a score of 7 would have 7 asterisks in it, it will match a score of 7, 8, 9 or greater.

Following is an example for Thunderbird, though it is applicable to other e-mail programs. We are going to create a rule that will go through the Junk folder looking for anything that has a spam level over 10, and immediately throw it away.

  1. Tools | Message Filters
  2. New
  3. Filter Name: Bad Spam (or whatever you want)
  4. Check Manually Run
  5. Uncheck Getting New Mail
  6. Check Match all of the following
  7. You most likely do not have a place for X-Spam-Level, so we must create one.
  8. In First rule, change Subject to Customize
    1. In box that pops up, enter X-Spam-Level (if it doesn’t already exist)
    2. Click “Ok”
  9. Now, select the X-Spam-Level
  10. Leave contains as the condition
  11. Enter 10 asterisks in the last part, ie **********
  12. Under Perform these actions
  13. Change Move Message to Delete Message
  14. Click Ok button