AWS Network Firewall: A Deep Dive in AWS Resources & Best Practices to Adopt
Network security continues to be a critical concern for organizations moving to the cloud. According to the 2024 State of Cloud Security report, 95% of organizations have experienced at least one cloud security incident in the past year, with 71% of those incidents being network-related. As infrastructure becomes more complex and distributed across multiple VPCs, accounts, and regions, traditional perimeter-based security approaches are proving inadequate. Organizations need comprehensive network protection that can scale with their infrastructure and provide granular control over traffic flows.
AWS Network Firewall addresses these challenges by providing a managed, stateful firewall service that protects entire VPCs with enterprise-grade security features. Unlike traditional hardware firewalls or host-based solutions, Network Firewall operates at the network layer, providing centralized protection for all resources within a VPC while integrating seamlessly with other AWS security services. This managed approach eliminates the operational overhead of maintaining firewall infrastructure while providing the flexibility and control that enterprises require.
A recent survey by Cloud Security Alliance found that 68% of organizations using AWS have implemented some form of network firewall solution, with Network Firewall being the most commonly adopted service for VPC-level protection. Organizations report an average 45% reduction in security incidents after implementing comprehensive network firewall policies, demonstrating the real-world impact of proper network security controls. For teams managing infrastructure with Terraform, understanding how to properly configure and maintain Network Firewall resources is essential for building secure, scalable cloud architectures.
In this blog post we will learn about what AWS Network Firewall is, how you can configure and work with it using Terraform, and learn about the best practices for this service.
What is AWS Network Firewall?
AWS Network Firewall is a managed network security service that provides stateful firewall protection for Amazon Virtual Private Clouds (VPCs). It acts as a network layer security control that inspects and filters traffic flowing between subnets, VPCs, and external networks based on configurable rules and policies.
Unlike traditional firewalls that operate at a single point in the network, Network Firewall is designed to protect entire VPCs by creating inspection points where traffic is analyzed against security rules. The service provides both stateful and stateless traffic filtering capabilities, deep packet inspection, and integration with AWS security services like AWS WAF, AWS Shield, and Amazon GuardDuty. This comprehensive approach allows organizations to implement defense-in-depth strategies that protect against both known and emerging threats.
Network Firewall operates using a distributed architecture where firewall endpoints are automatically deployed across multiple Availability Zones within a VPC. This design ensures high availability and fault tolerance while providing consistent security policies across all network traffic. The service scales automatically to handle traffic loads without requiring manual intervention, making it suitable for both small applications and large enterprise workloads. Each firewall endpoint processes traffic independently, but all endpoints within a firewall share the same policy configuration, ensuring consistent security posture across the entire protected network.
Network Firewall Architecture and Components
The Network Firewall service consists of several key components that work together to provide comprehensive network protection. At the core is the firewall resource itself, which defines the configuration for a specific VPC and references the security policy that governs traffic inspection. Each firewall is associated with a firewall policy that contains the rules and rule groups used to evaluate traffic.
Firewall policies are composed of rule groups, which can be either stateless or stateful. Stateless rule groups evaluate each packet independently based on header information like source and destination IP addresses, ports, and protocols. These rules are processed in order of priority and are designed for high-performance filtering of simple traffic patterns. Stateful rule groups, on the other hand, maintain connection state information and can evaluate traffic based on the context of the communication session. This allows for more sophisticated filtering based on application protocols, connection patterns, and content inspection.
The firewall endpoints are the actual enforcement points where traffic inspection occurs. These endpoints are automatically deployed in specified subnets within the VPC and handle all traffic routing decisions based on the configured policies. When traffic flows through a firewall endpoint, it is evaluated against the firewall policy rules in a specific order: first stateless rules, then stateful rules, and finally any custom rule groups. This layered approach allows for both high-performance filtering and deep inspection based on the specific security requirements of the organization.
Traffic Flow and Inspection Process
Network Firewall integrates into the VPC routing architecture by becoming part of the traffic flow between subnets and external networks. When configured, the firewall endpoints receive traffic through route table configurations that direct specific traffic flows through the inspection points. This allows organizations to selectively protect critical network segments while maintaining flexibility in their network architecture.
The traffic inspection process follows a deterministic evaluation sequence. First, traffic is evaluated against stateless rules for basic filtering based on packet headers. These rules can allow, drop, or pass traffic to the next evaluation stage. Traffic that passes the stateless evaluation is then subjected to stateful inspection, which maintains connection state and can perform deep packet inspection based on application protocols.
For stateful inspection, Network Firewall supports a variety of protocols including HTTP, HTTPS, SSH, DNS, and many others. The service can inspect traffic payloads for malicious content, enforce application-specific security policies, and detect threats based on behavioral analysis. This capability is particularly valuable for protecting against advanced persistent threats, data exfiltration attempts, and application-layer attacks that traditional network security tools might miss.
Strategic Importance of Network Firewall
AWS Network Firewall represents a fundamental shift in how organizations approach network security in cloud environments. Traditional network security models were built around perimeter defense, where organizations created strong boundaries between internal and external networks. However, cloud infrastructure requires a more nuanced approach that provides granular control over traffic flows while maintaining the flexibility and scalability that cloud platforms offer.
The strategic importance of Network Firewall lies in its ability to provide centralized network security management across complex cloud architectures. Organizations typically operate multiple VPCs across different AWS accounts, regions, and business units. Without centralized network security controls, teams often implement inconsistent security policies or rely on host-based security measures that can be bypassed or misconfigured. Network Firewall solves this problem by providing a consistent, centrally managed security policy that can be applied across multiple VPCs and accounts.
Recent research by Gartner indicates that 78% of organizations plan to increase their investment in cloud network security services over the next two years, with managed firewall services being the top priority. The shift toward managed services is driven by the operational complexity of maintaining traditional firewall infrastructure in cloud environments and the need for security controls that can scale with dynamic cloud workloads.
Compliance and Regulatory Requirements
Many industries are subject to strict regulatory requirements that mandate specific network security controls. Healthcare organizations must comply with HIPAA regulations, financial services companies must meet PCI DSS standards, and government agencies must adhere to FedRAMP requirements. Network Firewall helps organizations meet these compliance requirements by providing auditable, centralized security controls that can be documented and validated by auditors.
The service provides comprehensive logging and monitoring capabilities that capture all traffic flows and security decisions. These logs can be integrated with AWS CloudTrail, Amazon CloudWatch, and third-party security information and event management (SIEM) systems to provide the audit trails required for compliance reporting. Organizations can demonstrate to auditors that network traffic is being inspected according to established security policies and that all security events are being logged and monitored.
Network Firewall also supports the principle of least privilege by allowing organizations to create granular security policies that only permit necessary traffic flows. This approach reduces the attack surface and helps organizations demonstrate that they are implementing appropriate security controls to protect sensitive data and systems.
Cost Optimization and Resource Efficiency
From a cost perspective, Network Firewall provides significant advantages over traditional approaches to network security. Organizations that previously deployed third-party firewall appliances in EC2 instances had to manage the operational overhead of maintaining these systems, including patching, scaling, and high availability configuration. Network Firewall eliminates this operational burden by providing a fully managed service that scales automatically based on traffic demand.
The service uses a consumption-based pricing model where organizations pay for the firewall endpoints and the amount of traffic processed. This approach allows organizations to optimize costs by only paying for the security controls they actually use. For organizations with variable traffic patterns, this can result in significant cost savings compared to over-provisioning traditional firewall infrastructure to handle peak loads.
Network Firewall also reduces the need for specialized security expertise within organizations. Traditional firewall management requires deep knowledge of network protocols, security threats, and firewall configuration. With Network Firewall, organizations can leverage AWS's security expertise and managed service capabilities while focusing their internal resources on business-specific security requirements.
Integration with AWS Security Ecosystem
Network Firewall is designed to integrate seamlessly with the broader AWS security ecosystem, providing organizations with a comprehensive security posture. The service works alongside AWS WAF for application-layer protection, AWS Shield for DDoS protection, and Amazon GuardDuty for threat detection. This integration allows organizations to implement layered security strategies that provide protection at multiple levels of the network stack.
The integration with AWS security services also provides enhanced threat intelligence capabilities. Network Firewall can consume threat intelligence feeds from AWS and third-party sources to automatically update security policies based on emerging threats. This capability helps organizations stay ahead of evolving security threats without requiring manual policy updates or constant monitoring of threat intelligence sources.
For organizations using AWS Control Tower, Network Firewall can be deployed as part of centralized security guardrails that ensure consistent security policies across all accounts and organizational units. This approach helps large enterprises maintain security consistency while allowing individual teams to maintain operational flexibility within their specific environments.
Key Features and Capabilities
Stateful and Stateless Traffic Filtering
Network Firewall provides both stateful and stateless traffic filtering capabilities, allowing organizations to implement comprehensive security policies that address different types of network threats. Stateless filtering provides high-performance packet inspection based on header information, while stateful filtering maintains connection state and can perform deep packet inspection based on application protocols.
The stateless filtering engine can process millions of packets per second with minimal latency, making it ideal for filtering based on simple criteria like source and destination IP addresses, ports, and protocols. This capability is particularly valuable for blocking known malicious IP addresses, implementing geo-blocking policies, or preventing traffic from specific network segments.
Stateful filtering provides more sophisticated security capabilities by maintaining information about network connections and evaluating traffic based on the context of the communication session. This allows Network Firewall to detect and prevent attacks that span multiple packets or connections, such as TCP sequence attacks, session hijacking attempts, and application-layer exploits.
Deep Packet Inspection and Protocol Support
Network Firewall supports deep packet inspection for a wide range of protocols and applications. The service can inspect HTTP and HTTPS traffic, SSH sessions, DNS queries, and many other protocols to detect malicious content, enforce application-specific security policies, and prevent data exfiltration attempts. This capability is particularly important for organizations that need to protect against advanced persistent threats and zero-day exploits.
The deep packet inspection engine uses signature-based detection to identify known threats and behavioral analysis to detect suspicious activity patterns. Organizations can configure custom rules to detect specific application behaviors, enforce data loss prevention policies, or block access to unauthorized services. This flexibility allows organizations to implement security policies that are tailored to their specific risk profile and compliance requirements.
Network Firewall also supports SSL/TLS decryption for inspecting encrypted traffic flows. This capability is essential for organizations that need to enforce security policies on encrypted communications while maintaining the privacy and integrity of sensitive data. The service provides centralized certificate management and can integrate with AWS Certificate Manager for simplified SSL/TLS certificate lifecycle management.
Centralized Policy Management
One of the key advantages of Network Firewall is its centralized policy management capabilities. Organizations can define firewall policies that are applied consistently across multiple VPCs and AWS accounts, ensuring that security policies are enforced uniformly throughout the organization. This centralized approach reduces the risk of policy inconsistencies and makes it easier to maintain security posture as the organization grows and evolves.
Firewall policies are defined using rule groups that can be shared across multiple firewalls. This approach allows organizations to create reusable security policies that can be applied to different environments while maintaining consistency. For example, organizations can create rule groups for common security policies like blocking malicious domains, enforcing data loss prevention policies, or implementing application-specific security controls.
The centralized policy management also supports versioning and change management capabilities. Organizations can track changes to firewall policies, roll back to previous versions if needed, and implement approval workflows for policy changes. This capability is particularly important for organizations that need to maintain audit trails for compliance purposes or implement change management processes for security policies.
High Availability and Automatic Scaling
Network Firewall is designed to provide high availability and automatic scaling capabilities that ensure consistent security protection even during traffic spikes or infrastructure failures. The service automatically deploys firewall endpoints across multiple Availability Zones within a VPC, providing redundancy and fault tolerance. If one firewall endpoint fails, traffic is automatically routed to other available endpoints without disrupting network connectivity.
The automatic scaling capabilities allow Network Firewall to handle varying traffic loads without requiring manual intervention. The service monitors traffic patterns and automatically adjusts capacity to maintain performance and availability. This capability is particularly important for organizations with variable traffic patterns or those that experience seasonal traffic spikes.
Network Firewall also provides traffic engineering capabilities that allow organizations to optimize network performance while maintaining security protection. The service can distribute traffic across multiple firewall endpoints based on traffic patterns, network topology, and performance requirements. This approach helps organizations maintain optimal network performance while ensuring that all traffic is properly inspected and filtered.
Integration Ecosystem
Network Firewall integrates with a comprehensive ecosystem of AWS services to provide organizations with a complete network security solution. The service works seamlessly with VPC networking components, security services, logging and monitoring tools, and infrastructure management services. This integration allows organizations to implement comprehensive security strategies that protect against a wide range of threats while maintaining operational efficiency.
At the time of writing there are 25+ AWS services that integrate with Network Firewall in some capacity. The most common integrations include VPC components for network routing, S3 buckets for log storage, and IAM policies for access control. Organizations also commonly integrate Network Firewall with CloudWatch for monitoring and alerting, KMS for encryption, and Route 53 for DNS filtering.
The integration with VPC networking components is particularly important because it determines how traffic flows through the firewall inspection points. Network Firewall integrates with subnets, route tables, and internet gateways to control traffic routing and ensure that all relevant traffic is inspected according to the configured security policies.
For logging and monitoring, Network Firewall integrates with Amazon CloudWatch Logs, Amazon S3, and Amazon Kinesis Data Streams. This integration allows organizations to capture comprehensive logs of all network traffic and security events, which can be used for security analysis, compliance reporting, and troubleshooting. The logs can be integrated with third-party SIEM systems or analyzed using Amazon Athena for advanced security analytics.
Network Firewall also integrates with AWS Config for configuration management and compliance monitoring. This integration allows organizations to track changes to firewall configurations, ensure that security policies are being applied correctly, and maintain compliance with regulatory requirements. The service can automatically detect configuration drift and alert administrators when firewall policies are not aligned with established security standards.
Pricing and Scale Considerations
Network Firewall uses a consumption-based pricing model that consists of two primary components: firewall endpoint charges and data processing charges. Organizations pay an hourly rate for each firewall endpoint deployed in their VPCs, regardless of the amount of traffic processed. Additionally, they pay for the volume of data processed through the firewall endpoints, measured in gigabytes processed per hour.
The firewall endpoint charges are based on the number of Availability Zones where the firewall is deployed. Each firewall endpoint costs approximately $0.395 per hour (prices may vary by region), which translates to roughly $285 per month per endpoint. For a typical multi-AZ deployment with three firewall endpoints, organizations can expect to pay around $855 per month for the base firewall infrastructure.
Data processing charges are based on the volume of traffic inspected by the firewall. The current rate is approximately $0.065 per GB of data processed. For organizations processing 1 TB of data per month, this would result in additional charges of about $65. However, organizations with higher traffic volumes may be eligible for volume discounts, and the actual costs will depend on traffic patterns and the specific inspection requirements.
Scale Characteristics
Network Firewall is designed to scale automatically based on traffic demand without requiring manual intervention. The service can handle traffic loads ranging from a few megabits per second to multiple gigabits per second per firewall endpoint. For organizations with higher traffic requirements, multiple firewall endpoints can be deployed across different Availability Zones to distribute the load and provide additional capacity.
The service provides consistent performance characteristics regardless of the traffic volume, with typical latency of less than 10 milliseconds for stateless filtering and less than 50 milliseconds for stateful inspection. These performance characteristics make Network Firewall suitable for real-time applications and high-throughput workloads that require low-latency network connections.
Network Firewall supports up to 100 firewall endpoints per AWS account by default, with the ability to request higher limits through AWS Support. Each firewall can be associated with multiple subnets and can protect multiple VPCs through appropriate routing configurations. This scalability allows organizations to implement comprehensive network security across large, complex cloud architectures.
Enterprise Considerations
For large enterprise deployments, Network Firewall provides several features that support complex organizational requirements. The service supports cross-account sharing of firewall policies, allowing organizations to implement consistent security policies across
Managing Network Firewall using Terraform
Network Firewall configuration in Terraform requires careful planning of network architecture and security policies. The service involves multiple interconnected components that must be properly configured to provide effective network protection.
Basic Network Firewall Deployment
The simplest Network Firewall setup involves creating a firewall with a basic policy and subnet mappings:
# Create a firewall policy first
resource "aws_networkfirewall_firewall_policy" "example" {
name = "example-firewall-policy"
firewall_policy {
stateless_default_actions = ["aws:pass"]
stateless_fragment_default_actions = ["aws:pass"]
stateless_rule_group_reference {
priority = 1
resource_arn = aws_networkfirewall_rule_group.allow_domains.arn
}
stateful_rule_group_reference {
resource_arn = aws_networkfirewall_rule_group.block_malicious.arn
}
}
tags = {
Name = "example-firewall-policy"
Environment = "production"
Purpose = "network-security"
}
}
# Create the Network Firewall
resource "aws_networkfirewall_firewall" "main" {
name = "production-firewall"
firewall_policy_arn = aws_networkfirewall_firewall_policy.example.arn
vpc_id = aws_vpc.main.id
delete_protection = true
# Define subnet mappings for firewall endpoints
subnet_mapping {
subnet_id = aws_subnet.firewall_subnet_az1.id
}
subnet_mapping {
subnet_id = aws_subnet.firewall_subnet_az2.id
}
# Configure logging destinations
logging_configuration {
log_destination_config {
log_destination = {
bucketName = aws_s3_bucket.firewall_logs.bucket
prefix = "network-firewall-logs/"
}
log_destination_type = "S3"
log_type = "FLOW"
}
log_destination_config {
log_destination = {
logGroup = aws_cloudwatch_log_group.firewall_alerts.name
}
log_destination_type = "CloudWatchLogs"
log_type = "ALERT"
}
}
tags = {
Name = "production-firewall"
Environment = "production"
SecurityLevel = "high"
ManagedBy = "terraform"
ComplianceScope = "pci-dss"
}
}
# Supporting VPC infrastructure
resource "aws_vpc" "main" {
cidr_block = "10.0.0.0/16"
enable_dns_hostnames = true
enable_dns_support = true
tags = {
Name = "production-vpc"
}
}
# Dedicated firewall subnets
resource "aws_subnet" "firewall_subnet_az1" {
vpc_id = aws_vpc.main.id
cidr_block = "10.0.1.0/24"
availability_zone = "us-west-2a"
tags = {
Name = "firewall-subnet-az1"
Type = "firewall"
}
}
resource "aws_subnet" "firewall_subnet_az2" {
vpc_id = aws_vpc.main.id
cidr_block = "10.0.2.0/24"
availability_zone = "us-west-2b"
tags = {
Name = "firewall-subnet-az2"
Type = "firewall"
}
}
This configuration creates a basic Network Firewall with logging enabled and subnet mappings across multiple availability zones. The delete_protection flag prevents accidental deletion of the firewall resource.
Advanced Multi-Tier Network Firewall Architecture
For enterprise deployments, Network Firewall often requires sophisticated rule groups and integration with other AWS services:
# KMS key for encryption
resource "aws_kms_key" "firewall_encryption" {
description = "KMS key for Network Firewall encryption"
deletion_window_in_days = 7
enable_key_rotation = true
policy = jsonencode({
Version = "2012-10-17"
Statement = [
{
Sid = "Enable IAM User Permissions"
Effect = "Allow"
Principal = {
AWS = "arn:aws:iam::${data.aws_caller_identity.current.account_id}:root"
}
Action = "kms:*"
Resource = "*"
},
{
Sid = "Allow Network Firewall Service"
Effect = "Allow"
Principal = {
Service = "network-firewall.amazonaws.com"
}
Action = [
"kms:Decrypt",
"kms:GenerateDataKey"
]
Resource = "*"
}
]
})
tags = {
Name = "network-firewall-kms-key"
Environment = "production"
Purpose = "firewall-encryption"
}
}
# Advanced stateful rule group
resource "aws_networkfirewall_rule_group" "advanced_stateful" {
name = "advanced-stateful-rules"
type = "STATEFUL"
capacity = 1000
rule_group {
rules_source {
rules_source_list {
generated_rules_type = "DENYLIST"
target_types = ["HTTP_HOST", "TLS_SNI"]
targets = [
"badsite.com",
"malicious.example.com",
".suspicious-domain.net"
]
}
}
# Suricata compatible rules
rules_source {
rules_string = <<-EOT
alert http any any -> any any (msg:"Suspicious User-Agent"; content:"wget"; http_user_agent; sid:1; rev:1;)
alert tcp any any -> any 22 (msg:"SSH Brute Force Attempt"; threshold:type limit, track by_src, count 5, seconds 60; sid:2; rev:1;)
alert tcp any any -> any 3389 (msg:"RDP Access Attempt"; sid:3; rev:1;)
drop tcp any any -> any 445 (msg:"SMB Traffic Block"; sid:4; rev:1;)
EOT
}
# Rule variables for flexibility
rule_variables {
ip_sets {
key = "INTERNAL_NETWORKS"
ip_set {
definition = ["10.0.0.0/8", "172.16.0.0/12", "192.168.0.0/16"]
}
}
ip_sets {
key = "DMZ_NETWORKS"
ip_set {
definition = ["10.0.100.0/24", "10.0.101.0/24"]
}
}
port_sets {
key = "WEB_PORTS"
port_set {
definition = ["80", "443", "8080", "8443"]
}
}
}
}
tags = {
Name = "advanced-stateful-rules"
Environment = "production"
RuleType = "stateful"
Purpose = "threat-detection"
}
}
# Complex firewall policy with multiple rule groups
resource "aws_networkfirewall_firewall_policy" "enterprise" {
name = "enterprise-firewall-policy"
firewall_policy {
stateless_default_actions = ["aws:forward_to_sfe"]
stateless_fragment_default_actions = ["aws:forward_to_sfe"]
# Stateless rule group for high-speed filtering
stateless_rule_group_reference {
priority = 1
resource_arn = aws_networkfirewall_rule_group.stateless_allow.arn
}
stateless_rule_group_reference {
priority = 2
resource_arn = aws_networkfirewall_rule_group.stateless_deny.arn
}
# Stateful rule groups for deep packet inspection
stateful_rule_group_reference {
resource_arn = aws_networkfirewall_rule_group.advanced_stateful.arn
priority = 1
}
stateful_rule_group_reference {
resource_arn = aws_networkfirewall_rule_group.compliance_rules.arn
priority = 2
}
# TLS inspection configuration
tls_inspection_configuration_arn = aws_networkfirewall_tls_inspection_configuration.enterprise.arn
}
tags = {
Name = "enterprise-firewall-policy"
Environment = "production"
SecurityLevel = "maximum"
ComplianceReq = "pci-dss-sox"
}
}
# Production Network Firewall with comprehensive configuration
resource "aws_networkfirewall_firewall" "enterprise" {
name = "enterprise-production-firewall"
firewall_policy_arn = aws_networkfirewall_firewall_policy.enterprise.arn
vpc_id = aws_vpc.production.id
delete_protection = true
# Firewall encryption with KMS
encryption_configuration {
key_id = aws_kms_key.firewall_encryption.arn
type = "CUSTOMER_KMS"
}
# Multi-AZ deployment for high availability
subnet_mapping {
subnet_id = aws_subnet.firewall_subnet_az1.id
ip_address_type = "IPV4"
}
subnet_mapping {
subnet_id = aws_subnet.firewall_subnet_az2.id
ip_address_type = "IPV4"
}
subnet_mapping {
subnet_id = aws_subnet.firewall_subnet_az3.id
ip_address_type = "IPV4"
}
# Comprehensive logging configuration
logging_configuration {
# Flow logs to S3
log_destination_config {
log_destination = {
bucketName = aws_s3_bucket.firewall_flow_logs.bucket
prefix = "flow-logs/"
}
log_destination_type = "S3"
log_type = "FLOW"
}
# Alert logs to CloudWatch
log_destination_config {
log_destination = {
logGroup = aws_cloudwatch_log_group.firewall_alerts.name
}
log_destination_type = "CloudWatchLogs"
log_type = "ALERT"
}
# TLS inspection logs
log_destination_config {
log_destination = {
bucketName = aws_s3_bucket.firewall_tls_logs.bucket
prefix = "tls-inspection/"
}
log_destination_type = "S3"
log_type = "TLS"
}
}
tags = {
Name = "enterprise-production-firewall"
Environment = "production"
SecurityLevel = "maximum"
HighAvailability = "true"
DataClassification = "confidential"
BackupRequired = "true"
MonitoringLevel = "comprehensive"
}
}
# Supporting infrastructure
resource "aws_s3_bucket" "firewall_flow_logs" {
bucket = "enterprise-firewall-flow-logs-${random_id.bucket_suffix.hex}"
tags = {
Name = "firewall-flow-logs"
Environment = "production"
Purpose = "security-logging"
}
}
resource "aws_s3_bucket" "firewall_tls_logs" {
bucket = "enterprise-firewall-tls-logs-${random_id.bucket_suffix.hex}"
tags = {
Name = "firewall-tls-logs"
Environment = "production"
Purpose = "tls-inspection-logging"
}
}
resource "random_id" "bucket_suffix" {
byte_length = 8
}
# CloudWatch Log Group for alerts
resource "aws_cloudwatch_log_group" "firewall_alerts" {
name = "/aws/networkfirewall/alerts"
retention_in_days = 90
kms_key_id = aws_kms_key.firewall_encryption.arn
tags = {
Name = "firewall-alerts"
Environment = "production"
Purpose = "security-monitoring"
}
}
data "aws_caller_identity" "current" {}
This advanced configuration demonstrates enterprise-grade Network Firewall deployment with encryption, comprehensive logging, and multi-AZ high availability. The firewall integrates with KMS for encryption, multiple S3 buckets for different log types, and CloudWatch for real-time monitoring.
The configuration includes sophisticated rule groups with both stateless and stateful filtering, TLS inspection capabilities, and comprehensive tagging for governance and compliance requirements. The multi-subnet deployment ensures high availability and fault tolerance across multiple availability zones.
Best practices for Network Firewall
Implementing AWS Network Firewall correctly is critical for your network security posture. These best practices will help you maximize the effectiveness of your firewall deployment while maintaining optimal performance and security.
Use Centralized Policy Management
Why it matters: Managing firewall policies across multiple VPCs and accounts can quickly become complex and error-prone. A centralized approach ensures consistency and reduces the risk of misconfigurations.
Implementation: Deploy Network Firewall policies using AWS Firewall Manager or centralized Terraform configurations. Create standardized policy templates that can be reused across different environments.
# Create a central policy repository
aws networkfirewall create-firewall-policy \\
--firewall-policy-name "corporate-baseline-policy" \\
--firewall-policy file://baseline-policy.json
Store your policy definitions in version control and use infrastructure-as-code tools to deploy them consistently. This approach allows for proper change tracking and rollback capabilities when needed.
Implement Layered Security Architecture
Why it matters: Network Firewall works best as part of a comprehensive security strategy. Relying on a single security control creates potential single points of failure.
Implementation: Position Network Firewall strategically within your network architecture alongside other security controls. Use it in conjunction with NACLs, security groups, and AWS WAF for comprehensive protection.
resource "aws_networkfirewall_firewall" "inspection_firewall" {
name = "inspection-firewall"
firewall_policy_arn = aws_networkfirewall_firewall_policy.corporate_policy.arn
vpc_id = aws_vpc.inspection_vpc.id
subnet_mapping {
subnet_id = aws_subnet.firewall_subnet_az1.id
}
subnet_mapping {
subnet_id = aws_subnet.firewall_subnet_az2.id
}
tags = {
Environment = "production"
Purpose = "traffic-inspection"
}
}
Consider implementing inspection VPCs for centralized traffic filtering across multiple workload VPCs. This hub-and-spoke model provides better visibility and control over inter-VPC traffic.
Configure Comprehensive Logging and Monitoring
Why it matters: Without proper logging, you cannot effectively monitor threats, troubleshoot issues, or maintain compliance. Network Firewall generates valuable security intelligence that needs to be captured and analyzed.
Implementation: Enable all three types of logging: alert logs, flow logs, and TLS inspection logs. Send logs to multiple destinations for redundancy and different analytical purposes.
# Configure logging to S3 and CloudWatch
aws networkfirewall put-logging-configuration \\
--firewall-arn arn:aws:network-firewall:region:account:firewall/firewall-name \\
--logging-configuration '{
"LogDestinationConfigs": [
{
"LogType": "ALERT",
"LogDestination": {
"logDestination": "s3-bucket-name",
"logDestinationType": "S3"
}
},
{
"LogType": "FLOW",
"LogDestination": {
"logDestination": "log-group-name",
"logDestinationType": "CloudWatchLogs"
}
}
]
}'
Set up CloudWatch alarms for critical security events and integrate with AWS Security Hub for centralized security findings management. Regular log analysis helps identify attack patterns and optimization opportunities.
Optimize Rule Groups for Performance
Why it matters: Poorly structured rule groups can impact network performance and increase costs. The order and efficiency of rules directly affects processing speed and firewall throughput.
Implementation: Organize rules logically with the most frequently matched rules at the top. Use stateful rule groups for connection tracking and stateless rule groups for simple packet filtering.
resource "aws_networkfirewall_rule_group" "allow_outbound_web" {
name = "allow-outbound-web"
type = "STATEFUL"
capacity = 100
rule_group {
rules_source {
stateful_rules {
action = "PASS"
header {
destination = "ANY"
destination_port = "443"
direction = "FORWARD"
protocol = "TCP"
source = "10.0.0.0/8"
source_port = "ANY"
}
}
}
}
}
Regularly review and optimize rule groups based on traffic patterns and performance metrics. Remove unused rules and consolidate similar rules where possible to improve efficiency.
Implement Proper Subnet Design
Why it matters: Network Firewall requires dedicated subnets with specific routing configurations. Improper subnet design can lead to traffic loops, performance issues, or security gaps.
Implementation: Create dedicated firewall subnets in each Availability Zone where you deploy the firewall. Size these subnets appropriately based on your expected traffic volume.
# Create firewall endpoint subnets
aws ec2 create-subnet \\
--vpc-id vpc-12345678 \\
--cidr-block 10.0.1.0/28 \\
--availability-zone us-east-1a \\
--tag-specifications 'ResourceType=subnet,Tags=[{Key=Name,Value=firewall-subnet-1a}]'
Ensure proper routing table configurations to direct traffic through the firewall endpoints. Use separate route tables for firewall subnets and avoid asymmetric routing that can cause connection issues.
Regular Security Policy Updates
Why it matters: Threat landscapes evolve constantly, and your firewall policies must adapt to new attack vectors and changing business requirements.
Implementation: Establish a regular review cycle for firewall policies and rule groups. Use AWS Config rules to monitor policy compliance and detect unauthorized changes.
# Export current policy for review
aws networkfirewall describe-firewall-policy \\
--firewall-policy-arn arn:aws:network-firewall:region:account:firewall-policy/policy-name \\
--output json > current-policy.json
Implement a change management process that includes testing policy changes in non-production environments before deploying to production. Use AWS Firewall Manager for consistent policy enforcement across multiple accounts.
Cost Optimization Strategies
Why it matters: Network Firewall costs can grow significantly with traffic volume and rule complexity. Proper optimization ensures you get maximum security value while controlling expenses.
Implementation: Monitor your firewall capacity usage and right-size your deployments based on actual traffic patterns. Use CloudWatch metrics to track processed data and rule evaluation counts.
Consider implementing traffic engineering to optimize firewall placement and reduce unnecessary processing. Not all traffic needs to traverse the firewall - use strategic routing to process only traffic that requires inspection.
Disaster Recovery and High Availability
Why it matters: Network Firewall is a critical security component that must remain available during failures. Proper DR planning ensures business continuity and maintained security posture.
Implementation: Deploy firewall endpoints across multiple Availability Zones for high availability. Create backup policies and rule groups in your DR regions if required.
# Create firewall in multiple AZs
aws networkfirewall create-firewall \\
--firewall-name "prod-firewall" \\
--firewall-policy-arn $POLICY_ARN \\
--vpc-id $VPC_ID \\
--subnet-mappings SubnetId=subnet-12345,SubnetId=subnet-67890
Document your firewall configuration and maintain updated runbooks for common operational procedures. Regular backups of rule configurations and policies help ensure quick recovery from configuration errors.
Product Integration
AWS Network Firewall integrates with numerous AWS services to provide comprehensive network security across your infrastructure. At the time of writing, there are 50+ AWS services that integrate with Network Firewall in some capacity, including core networking services like VPC, subnets, and route tables, monitoring services like CloudWatch and CloudTrail, and security services like AWS WAF and Security Hub.
The service works seamlessly with VPC networking to provide centralized firewall capabilities across multiple subnets and Availability Zones. Network Firewall can be deployed in a hub-and-spoke architecture where it acts as a central inspection point for traffic flowing between VPCs, on-premises networks, and the internet.
Integration with CloudWatch enables comprehensive monitoring and alerting capabilities. Network Firewall automatically publishes metrics about packet counts, byte counts, and rule matches, allowing you to create custom dashboards and set up automated responses to security events.
For compliance and audit purposes, Network Firewall integrates with S3 buckets to store detailed flow logs and alert logs. These logs can be analyzed using services like Amazon Athena or fed into security information and event management (SIEM) systems for advanced threat detection.
The service also connects with AWS Security Hub to provide centralized security findings management, making it easier to correlate Network Firewall alerts with other security events across your AWS environment.
Use Cases
Centralized Network Security Management
Network Firewall excels in scenarios where organizations need to implement consistent security policies across multiple VPCs and AWS accounts. Rather than managing security groups and NACLs across hundreds of resources, teams can create centralized firewall policies that apply to all traffic flowing through designated inspection points.
This approach is particularly valuable for enterprises with complex multi-account architectures where maintaining consistent security posture across environments becomes challenging with traditional per-resource security controls.
Compliance and Regulatory Requirements
Organizations in heavily regulated industries like healthcare, finance, and government often require detailed network traffic inspection and logging capabilities. Network Firewall provides the granular control and comprehensive logging needed to meet compliance requirements such as PCI DSS, HIPAA, and SOC 2.
The service's ability to log all traffic flows, including allowed and denied connections, creates the audit trail necessary for regulatory compliance while providing the real-time protection required to prevent unauthorized access.
Hybrid Cloud Security
For organizations operating hybrid cloud environments, Network Firewall serves as a critical security control point for traffic flowing between on-premises networks and AWS. It can inspect and filter traffic from Direct Connect or VPN connections, ensuring that the same security policies apply regardless of whether traffic originates from the cloud or on-premises infrastructure.
This use case is particularly important for organizations gradually migrating to the cloud while maintaining strict security requirements for cross-network communication.
Limitations
Cost Considerations
Network Firewall operates on a consumption-based pricing model that can become expensive at scale. Organizations pay for firewall endpoints, data processing, and rule evaluations, which can result in significant monthly costs for high-traffic environments. The service charges for each gigabyte of data processed, making it potentially cost-prohibitive for applications with large data transfer requirements.
Performance Impact
While Network Firewall is designed for high performance, it does introduce latency to network traffic that passes through it. For applications requiring ultra-low latency, this additional processing time can impact user experience. The service can process millions of packets per second, but the actual throughput depends on the complexity of the rule sets and the types of inspection being performed.
Regional Availability
Network Firewall is not available in all AWS regions, which can limit deployment options for organizations with global infrastructure requirements. Additionally, the service cannot inspect traffic that doesn't flow through the firewall endpoints, so proper network architecture planning is essential to ensure comprehensive coverage.
Rule Complexity Management
While Network Firewall supports sophisticated rule sets, managing complex policies can become challenging as the number of rules grows. Organizations need to carefully plan their rule hierarchy and regularly review policies to prevent conflicts or performance degradation. The service also has limits on the number of rules per policy and the total size of rule groups.
Conclusions
The AWS Network Firewall service is a powerful managed solution for organizations requiring centralized network security controls. It supports comprehensive traffic inspection, detailed logging, and integration with the broader AWS security ecosystem. For organizations with complex multi-VPC architectures or strict compliance requirements, this service offers capabilities that go beyond traditional security groups and NACLs.
Network Firewall integrates seamlessly with core AWS networking services and provides the monitoring and logging capabilities necessary for enterprise security operations. However, organizations should carefully evaluate the cost implications and performance requirements before implementation.
The service's integration with over 50 AWS services makes it a natural choice for organizations already invested in the AWS ecosystem. However, you will most likely need to integrate your own security monitoring and incident response tools with Network Firewall as well. When implementing Network Firewall, careful planning is required to ensure proper traffic flow and rule management, as misconfigurations can impact network performance or create security gaps.
For organizations serious about network security in AWS, Network Firewall represents a significant step forward in managed security services, though it requires careful consideration of cost, performance, and operational complexity.