Firewall Hardware: Best Practices

TL;DR

Keep your firewall hardware secure and running smoothly with regular updates, strong passwords, proper configuration, monitoring, and a documented disaster recovery plan. Physical security is also vital.

1. Regular Firmware Updates

Firewall firmware contains critical security patches and bug fixes. Outdated firmware is a major vulnerability.

1. Check for updates regularly: Most firewalls have an automatic update feature. Enable it if possible. If not, check the manufacturer’s website at least monthly.
2. Test before deploying: Before updating your production firewall, test the new firmware in a lab environment to ensure compatibility with your network and applications.
3. Backup configuration: Always back up your current firewall configuration before applying any updates. This allows you to quickly revert if something goes wrong.

2. Strong Passwords & Multi-Factor Authentication

Default passwords are easily guessed. Use strong, unique passwords for all firewall accounts.

1. Change default credentials: Immediately change the default username and password upon installation.
2. Password complexity: Use a combination of uppercase and lowercase letters, numbers, and symbols. Aim for at least 12 characters.
3. Multi-Factor Authentication (MFA): Enable MFA wherever possible. This adds an extra layer of security by requiring a second form of verification (e.g., a code from your phone).

3. Proper Firewall Configuration

A misconfigured firewall is almost as bad as no firewall at all.

1. Least Privilege Principle: Only allow necessary traffic. Block everything else by default.
2. Rule Order Matters: Firewalls process rules in order. Place more specific rules higher in the list than general rules.
3. Network Address Translation (NAT): Use NAT to hide your internal network addresses from the internet.
4. Disable Unused Services: Turn off any firewall services you don’t need. This reduces the attack surface. For example, if you aren’t using remote access via SNMP, disable it.

4. Logging and Monitoring

Regularly review firewall logs to identify suspicious activity.

1. Enable logging: Configure the firewall to log all traffic, including accepted and denied connections.
2. Centralized Log Management: Send firewall logs to a Security Information and Event Management (SIEM) system for analysis.
3. Alerting: Set up alerts for critical events, such as blocked attacks or unauthorized access attempts.
4. Regular Review: Schedule regular reviews of firewall logs to identify trends and potential security issues.

5. Physical Security

Protect the physical hardware from unauthorised access.

1. Secure Location: Place the firewall in a locked server room or data centre with limited access.
2. Access Control: Restrict physical access to authorized personnel only.
3. Environmental Controls: Ensure proper temperature and humidity control to prevent hardware failure.

6. Disaster Recovery Plan

Prepare for the worst-case scenario.

1. Configuration Backups: Regularly back up your firewall configuration (as mentioned in step 1). Store backups offsite.
2. Redundancy: Consider deploying a redundant firewall to provide failover protection. High Availability (HA) configurations are common.
3. Testing: Regularly test your disaster recovery plan to ensure it works as expected. This includes restoring from backup and failing over to the secondary firewall.

7. Documentation

Keep detailed records of your firewall configuration, policies, and procedures.

1. Network Diagram: Maintain an up-to-date network diagram showing the location of all firewalls and their connections.
2. Configuration Documentation: Document all firewall rules, NAT settings, and other configurations.
3. Change Management: Keep a log of all changes made to the firewall configuration.