Thunderbird Tutorial – Using Spam and Junk Mail Filters

No one want to receive spam, but today it is almost inevitable that most e-mail addresses will eventually end up on spam lists. I have always protected my e-mail addresses, but recently ended up receiving more than 100 spam messages per day on my most important e-mail address used only by my business clients.

It turns out that a client thought she was doing me a favor when she posted it on a forum, along with a recommendation. As part of my battle to eliminate spam, I found that Thunderbird contains some amazingly powerful spam and junk mail controls that are very effective at filtering unwanted email. This tutorial shows you how to turn these filters on and configure them to meet your needs.

There are actually several methods for filtering out spam using Thunderbird’s tools. I used all of them in conjunction and found that Thunderbird effectively filtered out almost every undesirable message. It is also amazingly accurate and only very rarely grabs a legitimate message and identifies it as spam.

Pre-Filtering Spam Messages

The first level for setting up spam filtering is to do it at the server level or on your personal computer. If you have a web site, your hosting company might already offer spam filtering software, such as Spam Assassin or Spam Pal. This step is not absolutely necessary, but it does make the process of identifying and filtering spam more effective.

SpamAssassin is commonly found on Linux or Unix Apache servers. SpamAssassin checks messages coming through a hosting service’s e-mail system. It does not actually filter the spam out, but rather uses heuristic algorithms that analyze a message. It then assigns a spam score. Thunderbird can use this score to determine if a message is likely to be spam. If your web site runs on Unix or Linux and uses a control panel such as Pleske or cPanel, check to see if SpamAssassin is included. You will find it under Mail, SpamAssassin. If the message near the top indicates that SpamAssassin is disabled, click the box labeled Enable SpamAssassin. Do not click the box labeled Enable Spam Box.

SpamPal is a different type of filtering system that installs on your PC. SpamPal uses spam block lists (lists of IP addresses used by spammers) to identify spam messages. I have not tried it, but if your hosting company does not use SpamAssassin, or if you do not have a web site (and therefore do not use a hosting company), you might want to try installing it. You will find it at

Configuring Junk Mail Controls in Thunderbird

The first step is to configure Junk Settings.

  1. Select Account Settings from the Tools menu. Thunderbird allows you to configure each e-mail address separately.
  2. Select Junk Settings under one of your e-mail addresses.
  3. Check all of the boxes in the Junk Settings display. If you don’t use SpamAssassin or SpamPal, skip that checkbox. If you do use one of these tools, make sure the box is checked and the proper filter selected.
  4. Checking "Move new junk messages to Junk folder" will create a Junk folder under the selected e-mail address. You can set the nuber of days before spam is deleted from the junk folder. It is a good idea to move the messages to this folder so that you can periodically review it for messages that may not be spam.

Configuring Privacy Settings

  1. Select Tools, Options.
  2. Select the Privacy button.
  3. Select the Junk tab.
  4. Choose how you want spam to be handled when you manually select it when reviewing your e-mails. When you are viewing messages and you identify a spam message, you can click on the column to the left of the date to send the message to the Junk folder. This also helps the system identify spam messages.

Configuring Message Filters

When all else fails to identify spam, this is the way to do it. Message filters will search new messages for any keywords you designate. This section is pretty easy to figure out. Once again, you have to set up individual message filters for each e-mail address.

  1. Highlight an e-mail address in the main screen.
  2. Select Tools, Message Filters from the top menu.
  3. Click on the New button.
  4. Name your message filter at the top.
  5. Select the e-mail element that you wish to filter. Most spam keywords are going to be found in the Subject or Body.
  6. Select Contains.
  7. Enter the keyword or phrase you wish to use as a filter.
  8. Near the bottom of the displayed dialogue box, select the location to move any identified spam messages. The Junk folder for the current e-mail address is the most logical place for these messages so that you can review them.
  9. Click OK.

That’s about all there is to configuring Thunderbird to filter out spam messages. Although the configuration sections are a bit scattered throughout Thunderbird, once you know where to find them they are easy to use.


  1. robyn says

    This was not at all helpful to me
    I have all my mail coming into my inbox all marked as junk and no images showing
    I dont know how to remove this so I can then train what i want to actually go to junk

  2. Doogie says

    Hi Robyn

    You just do not understand Thunderbird.

    Thunderbird is designed to not display the images by default. Most good e-mail clients do this on purpose. A lot of spam messages contain images that link back to the spammer’s web server and use a code that verifies that your e-mail address is valid. If you view the image, your e-mail has been verified and will end up on umpteen million spam lists. NOT displaying images by default helps protect you from spammers.

    Your e-mail messages may be getting marked as junk by Spam Assassin, Spam Pal or a spam filter set up on your web server. These programs scan your messages before they are sent to you and send a code that Thunderbird uses to help determine if a message is spam.

    Take a look at Junk Settings under Account Settings for your e-mail account. Makes sure that “Enable adaptive junk mail controls for this account” is checked. Also make sure that “Do not mark mail as junk if sender is in Personal Address Book.” The names in your address book are your “white list” when this is checked. A white list in Thunderbird is the list of e-mails that you have previously sent a message to.

    If this does not get rid of the spam flags, then make sure that “Trust junk mail headers sent by” is unchecked.