Our email server uses MailScanner in combination with SpamAssassin to scan all inbound messages. Each email receives a spam score based on various content checks, authentication results, and rule matches (e.g. BAYES, HTML formatting, KAM rules, SPF checks, etc.).
These scores help determine how the system treats each message:
| Spam Score | Action |
|---|---|
| 0 – 3.9 | Considered clean – delivered to inbox as normal |
| 4 – 11.9 | Considered Low Scoring Spam – delivered but tagged (e.g. subject line modified to include “{Spam?}”) so users can review |
| 12+ | Considered High Scoring Spam – automatically deleted by MailScanner to reduce inbox clutter and block obvious spam |
📝 Tip: A single rule usually only adds a small amount to the total (e.g. 0.5 to 2.0), but multiple suspicious traits can quickly add up and push a message over the threshold.
SpamAssassin uses a rules-based scoring system.
Each rule has a pre-assigned score (positive or negative).
When an email is scanned, every matching rule’s score is added up.
The final total determines if the email is treated as clean, low spam, or high spam.
Example:
| Rule | Score |
|---|---|
| BAYES_50 | 0.8 |
| HTML_MESSAGE | 0.1 |
| KAM_MARKETINGBL_PCCC | 3.5 |
| MIME_HTML_ONLY | 2.5 |
| Total | 6.9 ✅ Tagged as Low Spam |
If you are the cPanel account holder and wish to adjust the low and high spam thresholds, you can do this through the MailScanner interface provided in your hosting control panel.
Login to your cPanel account
Use your hosting login credentials.
Scroll down to the “Email” section
Click on “MailScanner Front-End” (if not visible, your host may have disabled it).
Go to “Other Settings” or “User Spam Settings”
The exact wording may vary slightly depending on your server’s MailScanner plugin version.
Find the fields for “Low Scoring Spam” and “High Scoring Spam”
Default: Low = 4, High = 12 (as per your current configuration)
You can adjust these up or down depending on how strict you want the filtering to be.
Save the changes
MailScanner will apply the new thresholds almost immediately for future incoming mail.
Setting thresholds too low may cause legitimate marketing or HTML emails to be flagged as spam more often (false positives).
Setting thresholds too high could let more spam slip through to your inbox.
If you frequently receive legitimate emails that are tagged as spam, review the SpamAssassin score breakdown in the email headers to see which rules triggered. You can then whitelist trusted senders or adjust thresholds slightly.
If a trusted sender is consistently getting flagged:
Go to MailScanner → Whitelist in cPanel.
Add their email address or domain (e.g. example.com).
Save your changes.
This bypasses spam scoring for that sender.