Tuning SiteWorx spam filtering without losing legitimate mail

Collect examples of unwanted and wrongly classified messages with their headers. Record the current threshold and delivery action, and confirm how users inspect the Spam folder in webmail or IMAP.

1. Open Administration > Mail Options > Spam Settings and enable SpamAssassin if the service is available.
2. Review Spam Delivery before changing the score. Initially retain classified messages for inspection rather than choosing automatic deletion.
3. Adjust the score threshold conservatively. A lower threshold labels more messages as spam and can increase false positives.
4. Review subject rewriting and attachment handling, then submit the configuration. Add a narrowly scoped custom preference only when a specific requirement is understood.
5. Monitor normal correspondence and sample classified messages over several days. Revisit the threshold using actual outcomes rather than changing several options simultaneously.

Unwanted messages should be easier to review without disrupting legitimate invoices, password resets or customer enquiries. Confirm that each mailbox’s chosen mail client displays the relevant folder.

SpamAssassin’s delivery fallback differs from the separate Mail Filters action. In the documented SpamAssassin option, a missing Spam folder can result in inbox delivery. Verify actual mailbox behaviour before relying on a rule. A broad sender allow rule can also admit forged mail.

Review the results first. Legitimate messages can score unexpectedly, and a deletion action may prevent later recovery. Use evidence from your own mail flow before enabling irreversible handling.

• Creating a targeted SiteWorx email filter
• Choosing whether a SiteWorx domain should use a catchall
• Adding a monitored DMARC policy through SiteWorx
• Deleting a SiteWorx mailbox without losing needed messages

• InterWorx: Spam Assassin Guide
• spamassassin.apache.org: Mail Spamassassin Conf