Tech Matchups: AWS Network Firewall vs Security Groups
Overview
AWS Network Firewall is a managed firewall service providing Layer 3-7 protection, with stateful and stateless rules for VPC traffic.
Security Groups are instance-level, stateful firewalls controlling Layer 3-4 traffic for AWS resources like EC2 or RDS.
Both secure VPCs: Network Firewall for advanced threat protection, Security Groups for basic access control.
Section 1 - Protection Scope and Layers
Network Firewall protects at Layers 3-7, inspecting packets and payloads—e.g., blocking SQL injection via Suricata rules. Deployed at VPC or subnet boundaries.
Security Groups operate at Layers 3-4, controlling IP/port access—e.g., allowing TCP 80 to an EC2 instance. Applied per instance, stateful.
Scenario: Network Firewall stops malware traffic; Security Groups restrict SSH access.
Section 2 - Threat Detection and Rules
Network Firewall uses stateful (connection tracking) and stateless (packet-based) rules, plus Suricata for deep packet inspection—e.g., detecting XSS in HTTP payloads.
Security Groups use stateful rules only, filtering by IP, port, and protocol—e.g., allowing 10.0.0.0/16 on TCP 443. No payload inspection.
Scenario: Network Firewall blocks a DDoS attack; Security Groups limit database access. Network Firewall is proactive; Security Groups are reactive.
Section 3 - Cost and Management
Network Firewall charges per firewall-hour ($0.395 in us-east-1) and data processed ($0.065/GB). Example: 1TB/month costs ~$466.40 ($360 hourly + $106.40 data).
Security Groups are free, included with VPC resources. No cost for rules or evaluations.
Network Firewall requires rule group management; Security Groups are simpler, managed per instance.
Scenario: Network Firewall for regulated environments; Security Groups for general use.
Section 4 - Use Case Scenarios
Network Firewall suits compliance-driven or high-risk environments—e.g., protecting a financial app from Layer 7 attacks.
Security Groups fit standard VPC security—e.g., controlling access to web servers or databases.
Scenario: Network Firewall for a payment gateway; Security Groups for an internal CMS.
Section 5 - Comparison Table
| Aspect | Network Firewall | Security Groups |
|---|---|---|
| Layers | 3-7 | 3-4 |
| Protection | Stateful/Stateless, Suricata | Stateful, IP/Port |
| Cost | Hourly + Data | Free |
| Management | Rule Groups | Per Instance |
| Best For | Advanced Threats | Basic Access |
Network Firewall for deep protection, Security Groups for simple control. Combine for robust security.
Conclusion
AWS Network Firewall and Security Groups offer complementary VPC security. Network Firewall provides advanced Layer 3-7 protection, ideal for compliance or high-risk apps. Security Groups deliver simple, instance-level Layer 3-4 control, suitable for most VPC resources.
Weigh protection (advanced vs. basic), cost (paid vs. free), and complexity (rules vs. instance). Use Network Firewall for critical apps, Security Groups for general access—or combine: Network Firewall at VPC boundaries, Security Groups per instance.