AWS Network Firewall is a managed stateful network firewall and intrusion detection and prevention service designed to protect Amazon Virtual Private Cloud (VPC) environments. It provides fine-grained control over network traffic and is essential for organizations dealing with complex multi-account…AWS Network Firewall is a managed stateful network firewall and intrusion detection and prevention service designed to protect Amazon Virtual Private Cloud (VPC) environments. It provides fine-grained control over network traffic and is essential for organizations dealing with complex multi-account and multi-VPC architectures.
Key features include:
**Stateful Inspection**: Network Firewall maintains connection state information, allowing it to make intelligent decisions about traffic based on the full context of network sessions rather than individual packets.
**Rule Engine**: It supports both stateless and stateful rule groups. Stateless rules process packets independently, while stateful rules can inspect traffic patterns and maintain session awareness. You can use Suricata-compatible IPS rules for advanced threat detection.
**Integration with AWS Organizations**: For organizational complexity, Network Firewall integrates seamlessly with AWS Firewall Manager, enabling centralized security policy management across multiple accounts. This allows security teams to deploy consistent firewall rules organization-wide.
**Deployment Patterns**: Common architectures include centralized inspection VPCs using AWS Transit Gateway, where traffic from spoke VPCs routes through a dedicated inspection VPC containing Network Firewall endpoints. This hub-and-spoke model simplifies management while providing comprehensive traffic inspection.
**Scalability**: The service automatically scales with traffic demands, eliminating the need to manage underlying infrastructure. Firewall endpoints are deployed per Availability Zone for high availability.
**Logging and Monitoring**: Network Firewall integrates with CloudWatch, S3, and Kinesis Data Firehose for comprehensive logging, enabling security teams to analyze traffic patterns and investigate incidents.
**Domain Filtering**: It supports domain name filtering for both HTTP and HTTPS traffic, allowing organizations to control access to specific websites and services.
For Solutions Architects, understanding Network Firewall is crucial when designing secure, compliant architectures that meet regulatory requirements while managing complexity across distributed AWS environments.
AWS Network Firewall: Complete Guide for AWS Solutions Architect Professional Exam
Why AWS Network Firewall is Important
AWS Network Firewall is a critical service for organizations dealing with complex networking requirements and security compliance. As enterprises migrate to AWS, they need robust, scalable network protection that integrates seamlessly with their VPC architecture. Understanding this service is essential for Solutions Architects designing secure, compliant, and scalable solutions for large organizations.
What is AWS Network Firewall?
AWS Network Firewall is a managed stateful network firewall and intrusion detection and prevention service for Amazon VPCs. It provides:
• Stateful inspection - Tracks connection states and makes decisions based on traffic context • Deep packet inspection - Analyzes packet contents beyond headers • Intrusion Prevention System (IPS) - Detects and blocks malicious traffic patterns • Web filtering - Controls access to websites based on domain names • Protocol detection - Identifies protocols regardless of port used
Network Firewall supports rules written in Suricata-compatible format, allowing organizations to import existing rule sets.
How AWS Network Firewall Works
Architecture Components:
1. Firewall - The main resource that connects your VPC to the firewall policy 2. Firewall Policy - Defines the monitoring and protection behavior using rule groups 3. Rule Groups - Collections of rules that define how to inspect and handle traffic
Deployment Model:
• Network Firewall deploys firewall endpoints in dedicated subnets within your VPC • Traffic is routed through these endpoints using VPC route tables • Typically deployed in a centralized inspection VPC with AWS Transit Gateway for multi-VPC architectures • Supports both distributed and centralized deployment models
Rule Types:
• Stateless rules - Evaluate each packet in isolation (like NACLs) • Stateful rules - Track connections and apply context-aware filtering • Managed rule groups - AWS-managed threat intelligence rules
Traffic Flow:
1. Traffic enters the firewall subnet via route table configuration 2. Stateless rules are evaluated first (pass, drop, or forward to stateful engine) 3. Stateful rules are then evaluated 4. Traffic is either allowed, dropped, or alerted based on rule actions
Key Integration Points
• AWS Transit Gateway - Centralized inspection for multiple VPCs • AWS Gateway Load Balancer - For third-party appliance integration • Amazon CloudWatch - Metrics and logging • Amazon S3 and CloudWatch Logs - Flow and alert log destinations • AWS Firewall Manager - Centralized policy management across accounts
Common Use Cases
• Filtering traffic between VPCs and the internet • Inspecting traffic between on-premises networks and AWS • Centralized egress filtering for multiple VPCs • Compliance requirements for network-level security controls • Protecting workloads from known malicious IP addresses and domains
Exam Tips: Answering Questions on AWS Network Firewall
Scenario Recognition:
• When questions mention deep packet inspection, IPS/IDS, or Suricata rules, think Network Firewall • Questions about centralized egress filtering across multiple VPCs typically involve Network Firewall with Transit Gateway • Domain-based filtering for outbound traffic points to Network Firewall capabilities • Requirements for stateful inspection at the VPC level suggest Network Firewall
Distinguish from Other Services:
• Security Groups - Instance-level, stateful, no deny rules, no logging • NACLs - Subnet-level, stateless, basic IP/port filtering only • AWS WAF - Layer 7, HTTP/HTTPS only, protects CloudFront, ALB, API Gateway • Network Firewall - VPC-level, Layers 3-7, full protocol inspection
Architecture Patterns to Remember:
• Centralized inspection VPC - Deploy Network Firewall in a dedicated VPC connected via Transit Gateway • Inspection subnet design - Firewall endpoints need their own subnets • Route table configuration - Critical for directing traffic through firewall endpoints
Key Exam Indicators:
• "Inspect and filter traffic based on protocol" → Network Firewall • "Block traffic to known malicious domains" → Network Firewall • "Centralized security inspection across accounts" → Network Firewall with Firewall Manager • "Import existing Suricata rules" → Network Firewall • "Meet compliance requirements for network intrusion detection" → Network Firewall
Cost and Performance Considerations:
• Network Firewall charges per endpoint per hour plus data processed • For high availability, deploy endpoints in multiple Availability Zones • Firewall endpoints scale automatically based on traffic
Common Exam Traps:
• Do not confuse Network Firewall with AWS WAF - WAF is for web application attacks at Layer 7 • Remember that Network Firewall requires proper route table configuration to work • Network Firewall cannot be deployed in the same subnet as your resources • Firewall Manager is for centralized policy management, not the firewall itself