Configure Plesk Server-Wide SpamAssassin Settings Carefully

Plesk’s server-wide SpamAssassin controls set a baseline for incoming mail to hosted mailboxes. These are administrator controls, not ordinary mailbox preferences. Platform, installed components and provider permissions determine which controls are available.

Configure the server baseline carefully

1. In the verified HTTPS Plesk administrator interface, open Tools & Settings > Spam Filter in the Mail group. Record the current configuration before changing it.
2. Enable server-wide SpamAssassin only as part of the intended mail configuration. Decide whether mailbox users may apply individual settings.
3. Review the required score and optional subject marker. A lower required score is more sensitive and can create more false positives; there is no threshold that perfectly identifies all unwanted mail.
4. On Linux, review the maximum scanner processes in relation to actual resources. Increasing it is not an unconditional speed improvement and can affect other services.
5. Save, reopen and verify the intended settings and actual mail-processing behavior.

Separate marking from deletion and greylisting

Plesk documents server-wide SpamAssassin marking rather than a server-wide automatic-delete policy through this page. Mailbox-level settings can differ and may permit deletion. Check both levels before assuming marked messages will be retained.

Greylisting is a separate mechanism available in supported configurations, typically rejecting an initial delivery attempt temporarily so a legitimate sender retries. It can delay mail and is not the same as SpamAssassin content scoring. Do not enable it simply because it appeared beside spam settings in an old screenshot.

Manage allow and block entries

Use the appropriate list to add the precise address or supported pattern, save and review it. To remove an entry, select only that entry and confirm removal. Sender allowlisting is not proof of identity and can bypass useful classification. Avoid a broad wildcard for a public email provider or all senders as a troubleshooting shortcut.

Verify results and rollback narrowly

Inspect delivered message source for scoring/marking headers, review spam folders and sample legitimate messages after a change. A saved checkbox does not establish that every route or message size is scanned. Confirm the installed service and logs if headers are absent. Roll back only the relevant setting if legitimate mail is disrupted, preserving redacted evidence for a support ticket.

References: Plesk SpamAssassin configuration and Plesk antispam mechanisms.

Reviewed October 15, 2026. Documentation review only; no Plesk service, policy or customer message was changed or tested.