As businesses scale their AWS infrastructure, managing security and network traffic across multiple VPCs can become complex and inefficient. The solution? Deploying a Central Network VPC — also known as a Hub VPC — where all traffic from connected VPCs is routed through centralized firewalls for inspection and control.
In this blog, we’ll explore the Central Network VPC use case, its architecture, and why centralizing your network security in AWS is a best practice for modern cloud environments.
What is a Central Network VPC?
A Central Network VPC (Hub VPC) acts as a centralized networking and security layer within your AWS infrastructure. All application VPCs (spoke VPCs) connect to this Network VPC, where centralized firewalls and monitoring solutions inspect traffic entering or leaving the cloud environment.
Use Case: Centralized Firewall for Multi-VPC Architecture
In large AWS deployments, you may have:
- Separate VPCs for Production, UAT, and Development.
- Users connecting via VPN or Direct Connect.
- Web servers hosted in ECS or EC2.
- Sensitive workloads requiring strict security policies.
By routing all inter-VPC and external traffic through a Central Network VPC firewall, you can:
- Inspect and filter traffic centrally.
- Enforce consistent security policies.
- Simplify network management.
How It Works: High-Level Architecture
- Central Network VPC
- Hosts next-generation firewalls (AWS Network Firewall or third-party appliances like Palo Alto, Fortinet).
- Internet Gateway, NAT Gateway, and VPN connections terminate here.
- Monitors all ingress and egress traffic.
- Spoke VPCs (Application VPCs)
- Separate VPCs for various workloads.
- Connected to the Central Network VPC via AWS Transit Gateway.
- Traffic Flow
- Spoke VPCs send all traffic (internet-bound or inter-VPC) via Transit Gateway to Central Network VPC.
- Firewall inspects traffic before forwarding it to its destination.
- Return traffic also passes through the same firewall for consistent control.
Why Route All Traffic Through Network VPC Firewall?
- 🔒 Centralized Security Control: Enforce uniform security rules and reduce gaps.
- 📊 Simplified Monitoring: Single point for logging and monitoring with services like CloudWatch and VPC Flow Logs.
- 📈 Scalability: Transit Gateway efficiently connects multiple VPCs without complex peering.
- ⚙️ Operational Efficiency: Easier to manage firewall policies from a central point.
- 💰 Cost Optimization: Reduces operational overhead compared to deploying firewalls in every VPC.
Benefits of Centralized Network Infrastructure in AWS
1️⃣ Improved Security Posture
- Central inspection using AWS Network Firewall or third-party security appliances.
- Easier compliance management with centralized logs and reports.
2️⃣ Simplified Architecture
- Replace complex VPC Peering with AWS Transit Gateway.
- Eliminate scattered firewall deployments.
3️⃣ Cost Savings
- Reduce firewall licensing costs by consolidating.
- Simplify infrastructure, reducing management overhead.
4️⃣ Scalable and Flexible
- Easily onboard new VPCs and applications.
- Dynamically scale firewalls using AWS Autoscaling features.
5️⃣ Consistent Access Control
- Use centralized route tables and security policies.
- Ensure all workloads adhere to the same security framework.
AWS Services Typically Involved
- AWS Transit Gateway
- AWS Network Firewall / Third-Party Firewall Appliances
- Amazon CloudWatch / VPC Flow Logs
- IAM Policies & Security Groups
- S3 for Logging and Storage
- AWS Direct Connect / VPN Gateway
Best Practices for Central Network VPC Deployment
- Use Multi-AZ deployment for high availability of firewalls.
- Enable flow logging for monitoring and audits.
- Use automation tools like AWS CloudFormation or Terraform for consistent deployments.
- Regularly review and update firewall policies.
- Implement least privilege principle across VPC connections.
Conclusion
In complex AWS environments, deploying a Central Network VPC provides both enhanced security and operational simplicity. By routing all VPC traffic through a centralized firewall infrastructure, you create a controlled, scalable, and secure network foundation for your cloud workloads.
Whether you’re running multiple microservices, handling sensitive data, or managing large enterprise applications, centralizing your network architecture is a future-proof approach to cloud security.