How to Train Your Spam Filter by Marking Messages as Spam or Not Spam

Your email filter does not just rely on fixed rules. It also learns from what you tell it. When you mark a message as spam or not spam in your webmail, you are training the filter to recognize similar mail in the future. This is different from turning the filter on or adjusting how aggressive it is: it is a day-to-day habit that makes the existing filter smarter for your specific inbox.

How This Works

Your mailbox has a system folder, usually named Spam or Junk. When you move a message into that folder using the correct button, the system reads the message and updates its spam filter with what it learned. Moving a message out of that folder, back into your inbox, has the opposite effect: it tells the filter that message was wrongly flagged.

Simply deleting a spam message or ignoring it in your inbox does not train anything. You have to use the specific action described below for the training to happen.

In cPanel

1. Log in to Webmail for your email account.
2. Open the message you want to train the filter with.
3. To mark it as spam, click Spam (or Mark as Spam, depending on your webmail client). This moves the message into your Spam folder and updates your filter.
4. If a genuine message ends up in your Spam folder, open it there and click Not Spam to move it back to your Inbox and correct the filter.

In DirectAdmin

1. Log in to Webmail for your email account.
2. Open the message you want to train the filter with.
3. To mark it as spam, click Mark as Junk (or Spam). This moves the message into your Junk folder and updates your filter.
4. If a genuine message ends up in your Junk folder, open it there and click Not Junk to move it back to your Inbox and correct the filter.

If you use a desktop or mobile email app instead of webmail, moving a message into the account's Spam or Junk folder usually has the same training effect, since it is a folder on the mail server, not just on your device. Dragging a message into a local-only folder your app created will not work.

Tips for Better Results

• Train with a handful of messages rather than just one. The filter improves faster when it sees several examples of the same type of mail.
• Correct mistakes as soon as you spot them. If a newsletter or invoice keeps landing in Spam, marking it Not Spam a few times usually fixes it going forward.
• If one sender keeps getting flagged even after you correct it repeatedly, consider whitelisting that sender directly instead of relying on training alone.

If you have not yet turned SpamAssassin on for your account or want to adjust how strict it is, see How to Enable SpamAssassin and Adjust Its Sensitivity.