How to Reduce Spam on Your cPanel Server with Exim and WHM Tweaks

Spamming is a common issue for cPanel-based servers, and failing to prevent it can lead to IP blacklisting and email deliverability issues. By adjusting Exim and WHM settings, you can significantly reduce spam. Here’s how to configure your server to block unwanted emails.

1. Configure Exim to Block Spam Emails

Exim is the default mail transfer agent (MTA) for cPanel. Adjusting its settings can help filter out spam effectively.

Steps to Configure Exim:

  1. Log in to your WHM control panel as root.
  2. Navigate to Main >> Service Configuration >> Exim Configuration Manager.
  3. Enable RBL filtering:
    • Go to Basic Editor >> RBLs
    • Switch RBL filtering to ON
    • Optionally, add more RBLs from the manage option
  4. Enable Sender Verification Callouts = ON
  5. Enable Sender Verification = ON
  6. Enable Reject SPF failures = ON
  7. Click Save to apply the changes.

These settings will help prevent most spam emails from reaching your inbox.

2. Adjust WHM Tweak Settings for Better Email Control

Further improving email security requires modifying WHM’s Tweak Settings. Here’s how:

Steps to Modify Tweak Settings:

  1. Log in to WHM as root.
  2. Go to Main >> Server Configuration >> Tweak Settings.
  3. Modify the following settings:
    • Initial default/catch-all forwarder destination = Fail (Prevents spammers from targeting your domain’s catch-all address)
    • Max hourly emails per domain = 200 (Limits outbound spam from compromised accounts)
    • Count mailman deliveries towards a domain’s email limit (Ensures mailing lists don’t exceed email limits)

3. Need Expert Support? @CustomerPanel Has You Covered

If you’re still experiencing email spam issues, let our experts at UnderHost Support assist you. Our managed hosting solutions come with advanced email security configurations to keep your mail server safe.