How can I display the Spam Confidence Level (SCL) score in Outlook Web Access (OWA)?

Posted on January 8, 2009 by Daniel Petri in Anti-Spam Solutions with 0 Comments

Microsoft Exchange Intelligent Message Filter is a product developed by Microsoft to help companies reduce the amount of unsolicited commercial e-mail (UCE), or spam, received by users. You can read more about IMF on theĀ Block Spam with Exchange 2003 Intelligent Message Filter page.

When an external user sends e-mail messages to an Exchange server with Intelligent Message Filter enabled, IMF evaluates the textual content of the messages and assigns the message a rating based on the probability that the message is UCE or spam. All incoming messages are marked with a Spam Confidence Level (or SCL) rating.

SCL is a “rating system” that on a scale from -1 (only used for authenticated users) to 10, will tell Outlook or OWA whether or not the e-mail should be moved to the Junk E-mail folder (depending on the users settings). Note that not all messages might be transferred to the store (i.e. the users mailbox) depending on the settings on the IMF tab. Read more about how to Configure Intelligent Message Filter in Exchange 2003 SP2.

Viewing this SCL rating might be beneficial in some cases, especially when evaluating the effectiveness of IMF right before beginning to actually delete messages instead of just rating them or archiving them (read View Intelligent Message Filter Archive).

You can view the SCL rating in Outlook. Read Display SCL Level in Outlook 2003 for more info.

In Outlook Web Access there are 2 methods for viewing the SCL rating. Please contact me in case you know of another method to do so and Ill update this page.

Method #1 – Follow up on the Outlook 2003 SCL rating tweak

After performing the steps outlined in the Display SCL Level in Outlook 2003 article you will now be able to view the SCL rating via OWA. Follow these steps:

Note: If youre using Cached mode on your Outlook 2003 profile while performing the above steps, you must disable it in order to ensure that the view is saved on the server and available to OWA.

  1. Open Outlook 2003 and create a new view by going to View > Arrange by > Current View > Define Views.

  1. Select current view (the one that exposes the SCL column), press Copy.

  1. Name the copy “SCL View”. Select “This folder, visible to everyone”, press OK.

  1. Make sure SCL is listed in Fields, then click OK.

  1. Select the new SCL View. Click Apply View.

  1. Launch OWA and logon if necessary.
  2. Change view (next to folder name at the top of the page) to SCL View.


Done. You can now view the SCL rating in OWA from any computer.

Method #2 – As an independent add on

A great add-on written by Lee Derbyshire, a fellow Exchange MVP from the UK.

This add-on can be downloaded from here:

Download Message Headers and SCL rating add-on to OWA 2003 SP2 (12kb)

This OWA add-on will allow you to view message headers and IMF SCL in OWA 2003. It works only with OWA 2003 SP2, and it only works with the \Premium\ OWA interface.

  1. In order to install it, download the file from the above link (unzip it after you download it). Locate your util_View.js file. At the time of writing, it is in

(although this will change with future service packs and updates)

Lamer note: Substitute C:\ with the correct drive letter of your Exchange installation. You did install it on a different partition than your system partition, didnt you?

  1. Make a backup copy of the original file, and then replace it with the one in this archive.
  2. Your Web clients must clear their browser cache (to delete the old .js file). The next time they use OWA, they should see “View Headers” and “View SCL” added to the pop-up menu when right-clicking a message.

Cool, thanks Lee!


You Had Me At EHLO… : Exposing the Spam Confidence Level (SCL) in OWA

You Had Me At EHLO… : Exposing SCL (Spam Confidence Level) in Outlook

Lee Derbyshires website