Change Management Procedures

Production firewall changes carry significant risk—a misconfigured rule can block legitimate traffic or create security vulnerabilities. Implementing robust change management procedures minimizes these risks while maintaining agility.

Pre-Implementation Testing: Test all firewall changes in non-production environments that mirror production configurations. Use automated testing tools to verify both positive cases (allowed traffic passes) and negative cases (blocked traffic is denied). Document test results and any deviations from expected behavior:

#!/bin/bash
# Firewall rule testing script

echo "Testing new firewall rules..."

# Test allowed connections
for port in 80 443; do
    timeout 5 nc -zv test-server.example.com $port
    if [ $? -eq 0 ]; then
        echo "✓ Port $port accessible"
    else
        echo "✗ Port $port blocked (unexpected)"
    fi
done

# Test blocked connections
for port in 22 3306; do
    timeout 5 nc -zv test-server.example.com $port
    if [ $? -ne 0 ]; then
        echo "✓ Port $port blocked"
    else
        echo "✗ Port $port accessible (unexpected)"
    fi
done

Implementation Windows: Schedule firewall changes during approved maintenance windows when possible. For emergency changes, follow expedited procedures that still maintain essential safeguards. Always have rollback plans ready:

# Firewall change runbook
change_id: FW-2024-0145
change_type: standard
environment: production
risk_level: medium

pre_implementation:
  - Backup current firewall configuration
  - Notify stakeholders of change window
  - Verify rollback procedures
  
implementation_steps:
  - Apply firewall changes to standby node
  - Test connectivity from multiple sources
  - Switchover traffic to updated node
  - Apply changes to primary node
  - Verify full functionality
  
rollback_procedure:
  - Restore backed up configuration
  - Restart firewall service
  - Verify connectivity restored
  - Document rollback reason
  
post_implementation:
  - Monitor logs for 30 minutes
  - Update documentation
  - Close change ticket