Enable SPF (Sender Policy Framework) and DKIM (DomainKeys Identified Mail) on Domino 12+ servers to identify and move untrusted mail to users' Junk folders.

For more information, you can find detailed documentation on HCL Product Documentation and HCL Notes and Domino Wiki . If you'd like, I can:

Users can add/remove senders from the Junk list in their mail file. 3. Best Practices & Tips

Anti-spam strategies for Lotus Notes (now HCL Notes/Domino) in 2026 involve a combination of built-in server-level controls and user-level client tools to manage junk email and phishing attacks. Modern approaches focus on using SMTP-inbound edge servers, SPF/DKIM validation, and third-party tools to handle sophisticated spam, as native filtering alone is generally considered insufficient for modern threats. 1. Server-Level Anti-Spam Measures (Domino Administration)

Notes/Domino has a "MailMaxFilters" setting. More than 100 rules can significantly slow down the router.

Many administrators use tools like MagicSpam, Symantec SMSDOM, or dedicated email security gateways (e.g., Barracuda) in front of Domino for better "zero-day" protection. 2. Client-Level Anti-Spam Measures (HCL Notes Client)