Summary

This article outlines the spam filtering levels provided by DuoCircle, including detailed descriptions of the mechanisms and configurations used to filter unwanted emails effectively.

Objective

To provide an understanding of DuoCircle's spam filtering options and help users select the most appropriate level for their needs.

Introduction

Spam emails pose significant challenges to email security. DuoCircle offers a multi-faceted approach to spam filtering, leveraging sender reputation, content analysis, and advanced tools to protect users from malicious or unwanted messages.

Prerequisites

Step-by-Step Instructions

1. IP Reputation

  • Spam filtering begins by evaluating the sender’s IP reputation.
  • DuoCircle utilizes Cyren.comfor:
    • Spam classification
    • Signature-based virus and outbreak detection

2. Sender Policy Framework (SPF)

  • SPF checks ensure that email senders are authorized.
  • SPF verification integrates with content checks before messages are processed by SpamAssassin.

Learn more about SPF: Sender Policy Framework

3. Message Content Analysis

  • Anti-Virus Scanning: Two-tiered scanning to detect malware and viruses.
  • Cyren Integration: Enhances spam filtering accuracy.
  • SpamAssassin:
    • A classification engine used as the final spam filtering step.
    • Scores messages only after passing other technical checks.

For additional details, visit: Spam Filtering

Spam Filtering Levels

Disabled

  • SPF: Ignored
  • Whitelist/Blacklist: Enabled
  • Use Case: Backup MX or mail servers with robust spam filtering.
  • Recommendation: Avoid using this level; instead, configure whitelists and blacklists appropriately.

Low

  • SPF: Enabled
  • Whitelist/Blacklist: Enabled
  • SpamAssassin Threshold: ±2.5
  • Effect:
    • Obvious spam is discarded or quarantined.
    • Other messages are tagged or forwarded.

Medium

  • SPF: Enabled
  • Whitelist/Blacklist: Enabled
  • SpamAssassin Threshold: ±4.2
  • Effect:
    • Effective balance between rejecting/quarantining spam and tagging/forwarding legitimate messages.
  • Recommendation: Default setting for most users.

High

  • SPF: Enabled
  • Whitelist/Blacklist: Enabled
  • SpamAssassin Threshold: ±6.5
  • Effect:
    • Aggressive filtering, which may block newsletters or some legitimate messages.

Monitoring Logs

Monitor email activity and spam filtering performance using the DuoCircle logging feature: Viewing Your Domain Message Log Files

Conclusion

DuoCircle’s spam filtering options offer flexible and robust solutions for managing unwanted emails. From IP reputation analysis to customizable filtering levels, users can ensure their inboxes remain secure and efficient.