Defense in Depth Strategy

The principle of defense in depth remains fundamental to production firewall deployment. Rather than relying on a single firewall layer, effective security implements multiple overlapping controls that protect against different threat vectors. This redundancy ensures that if one control fails or is bypassed, others continue providing protection.

Start with perimeter defenses at the network edge. Cloud provider firewalls, network appliances, or DDoS protection services filter malicious traffic before it reaches your infrastructure. These outer defenses handle volumetric attacks, known bad actors, and geographic restrictions. Next, implement network segmentation using VLANs, security groups, or network ACLs to isolate web servers from other infrastructure components. This segmentation limits lateral movement if an attacker compromises one system.

Host-based firewalls on individual web servers provide the final layer of defense. These firewalls understand the specific requirements of each server and can implement granular rules based on applications, users, and processes. The combination of network and host-based firewalls creates multiple decision points where malicious traffic can be identified and blocked, significantly improving overall security posture.