Quick Summary: Sudden spike in spam? Learn how hitting "Delete" actually stops your filter from learning, and find out the exact steps to permanently block malicious networks.

The Science Behind the Filter: What is SpamAssassin Bayesian?

Your Rebel Plesk hosting server uses an enterprise-grade security engine called SpamAssassin. Inside this engine is a smart, learning artificial intelligence called a Bayesian Filter.

Think of the Bayesian filter like a digital security guard that needs to be trained:

• It analyzes the mathematical probability of words, links, and server headers inside your emails.

• When you tell it what spam looks like, it memorizes those specific "fingerprints."

• Over time, it gets smarter and automatically blocks similar messages at the server gateway before they ever touch your inbox.

The One Mistake Most Users Make: The "Trash" Trap

When a sudden surge of spam hits your inbox, your natural instinct is to check the boxes and hit Delete to clean up your workspace.

Why this hurts your security: Moving a spam message to the Trash folder tells the server, "I am done with this email." It does not train the filter. Even worse, emptying your Trash completely destroys the raw email headers, preventing our senior engineers from finding the spammers' rotated IP networks if you ever need to escalate a ticket.

The Essential Do's and Don'ts for Plesk Users

✅ WHAT TO DO:

• Move Spam to the "Junk" or "Spam" Folder: When an unwanted email slips into your Inbox, explicitly move it to your designated Junk or Spam folder. This simple action triggers the Bayesian engine to scan the message and actively train itself to block future variants.
   

• Leave Samples Live for Support: If your spam volume is extremely high and you need to open a support ticket, leave a batch of those unread spam messages sitting live inside your Junk folder. This allows our Server Administrators to extract the raw network subnets and deploy server-wide firewall blocks.

❌ WHAT NOT TO DO:

• Do Not Just Hit Delete: Avoid moving active spam straight to the Trash folder.
   

• Do Not Unsubscribe From Malicious Spam: If the email looks dangerous, fake, or highly aggressive, never click the "Unsubscribe" link. Doing so confirms to the spammers that your email address is active and monitored, which will instantly double your spam volume.

Step-by-Step: How to Boost your SpamAssassin Scoring in Plesk

If you want to make your email filter more aggressive right now, you can adjust your threshold settings directly inside your control panel:

1. Log into your Plesk Hosting Dashboard.

2. Navigate to Mail > Mail Addresses and click on your email account.

3. Click on the Spam Filter tab.

4. Ensure the checkbox for "Switch on spam filtering for this email address" is active.

5. Expand the Advanced Settings option.

6. Adjust the Spam Filter Sensitivity (Score):

   • The default score is 7. * Lowering the number (e.g., to 5 or 4) makes the filter much more aggressive. Be careful: setting it too low might catch legitimate business emails!

By working together and feeding the Bayesian filter the correct data, we can keep your workspace completely secure and free of disruptions!