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mb-eval Service

Email evaluation engine providing fast preliminary scoring and routing decisions.

Overview

mb-eval performs fast pre-filtering evaluation before full content analysis:

  • Quick scoring - Lightweight checks before expensive scans
  • Fast path routing - Bypass full filtering for trusted senders
  • Early rejection - Block obvious spam/threats immediately
  • Load balancing - Distribute to appropriate filter workers

Reduces load on mb-filter by handling obvious cases quickly.

Key Functions

Fast Path Decisions

Email Arrives
  ↓
mb-eval Quick Check:
  • Whitelist? → Fast Path (skip full filtering)
  • Blacklist? → Immediate Reject
  • Known pattern? → Score and route
  • Unknown → Full filtering via mb-filter

Evaluation Criteria

  • Sender reputation - Historical behavior
  • Whitelist/blacklist - Immediate decisions
  • Basic header checks - Malformed headers, missing fields
  • Connection metadata - IP reputation, GeoIP
  • Rate limiting - Sender frequency checks

Configuration

Service file: /etc/systemd/system/mb-eval.service

Settings: 

# Enable fast path
sudo mb-config set eval.fast_path_enabled true

# Whitelist bypass
sudo mb-config set eval.whitelist_bypass true

# Early rejection
sudo mb-config set eval.early_reject_enabled true

Operations

sudo systemctl start mb-eval
sudo systemctl status mb-eval
sudo tail -f /var/log/mailborder/mb-eval.log

Performance

Statistics: 

sudo mb-eval-stats

Shows: - Fast path hits (whitelisted) - Early rejections (blacklisted) - Passed to full filtering - Average evaluation time

See Also