Mozilla Thunderbird Filters Guide

The J T Response email server uses Spam Assassin to mark messages likely top be spam.

In this post we are going to explain how to set up your own personal filters on Mozilla Thunderbird to move messages marked as SPAM to your Junk folder. We used Thunderbird version 31.2. If you have a different version the details may vary slightly.

To start we need to get to the part of Thunderbird were we can edit filters.

  1. Click on the mail box you wish to add the filter to (shown by the red arrow at the top of the image, below).
  2. Click on the Manage message filters button (shown by the red arrow at the bottom of the image).

This will display the Filter Manager  window that allows you to create, edit and delete filters.

If this is your first time in this part of Thunderbird you will most likely only have the option to add a new filter.

Now that we are in the Filter Manager.

To create a new filter you need to:

  1. Select which email account the filter is for. This is chosen near the top.
  2. Select the folder that you want to to run your filter on here we have chosen my Inbox.
  3. Click the New button located on the right.

This will display the Filter Rules window, which will allow you to set the rules of your filter.

Give the Filter a name e.g. Spam

Then click on subject and select customise.


This will display the Filter Rules window.

In the new message header put “X-Spam-Level” then click Add.


Then click OK this will take you back to the filter manager.

Then next you need to put 6 *’s in the empty box.

(If you find that too many messages are being marked as junk, you could increase the number of *’s. If you find that not enough are being marked as junk, you could reduce the number of *’s)



Then at the bottom where is says Move Message to change this to be “Set Junk Status to“.

Then click OK you will be returned to the main section of the filter manager.

All that is left to do now is click Run Now  to test the filter.




Date: January 15, 2015

Category: Email Client Guides

Author: Dean Taylor

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