Understanding AWS networking is crucial for designing scalable and secure cloud architectures. This guide breaks down key networking concepts in AWS, including VPC Peering, VPNs, Direct Connect, and security best practices. Let’s dive in! 👇
VPC Peering: Connecting Two VPCs Privately
VPC Peering allows two VPCs to communicate privately over AWS’s network, making them behave as if they are in the same network.
- VPC Peering is not transitive, meaning each VPC that needs to communicate must have a separate peering connection.
- Route tables must be updated in each VPC to enable communication.
- You can establish VPC Peering across AWS accounts.
VPC Endpoints: Private Access to AWS Services
AWS services are publicly exposed, but VPC Endpoints allow access over a private network instead of the public internet.
- Removes the need for IGW, and NAT Gateway.
There are two types:
- Interface Endpoint: Uses ENI (Elastic Network Interface) to connect to AWS services.
- Gateway Endpoint: Used as a route target in a route table (supports S3 & DynamoDB and is free!).
- Best Practice: Use Gateway Endpoint for S3 (free), and Interface Endpoint when connecting from on-premises, other VPCs, or different regions.
AWS Site-to-Site VPN: Connecting On-Premises to AWS
A secure way to connect your corporate data centre to AWS.
- Virtual Private Gateway (VGW): AWS side of the VPN connection.
- Customer Gateway (CGW): Customer-side device or software to connect to AWS.
- If CGW is behind a NAT device, use its public IP.
- Enable Route Propagation for VGW in route tables.
- If you need to ping EC2 from on-premises, enable ICMP protocol in the Security Group.
AWS VPN Cloud: Secure Communication Between Multiple Sites
- A low-cost hub-and-spoke model for connecting multiple VPNs.
- Ideal for primary or secondary network connectivity.
- It uses the public internet but remains secure.
AWS Direct Connect: Dedicated Private Connectivity
Provides a dedicated private connection from your on-premises data centre to AWS.
Use Cases:
- High-bandwidth applications.
- Real-time data feeds.
- Hybrid environments.
Dedicated Connection: 1 Gbps, 10 Gbps, 100 Gbps (physical Ethernet connection).
Hosted Connection: 50 Mbps to 10 Gbps (via AWS Direct Connect partners, scalable on demand).
For High Resiliency: Deploy connections in multiple locations for redundancy.
To connect multiple VPCs across regions, use Direct Connect Gateway.
AWS Transit Gateway: Scalable Multi-VPC & On-Premises Connectivity
- Enables transitive peering between thousands of VPCs and on-premises networks.
- It acts as a regional hub but supports cross-region peering.
- Works with Direct Connect Gateway and VPC connections.
- Use Case: Increase VPN bandwidth using ECMP (Equal Cost Multipath Routing) for multiple Site-to-Site VPNs.
VPC Traffic Mirroring: Monitoring & Inspecting Network Traffic
- Captures and inspects network traffic in your VPC.
- Routes traffic to security appliances for analysis.
- Helps with security investigations and troubleshooting.
AWS Networking Costs: Optimizing for Savings 💰
- Inbound traffic to EC2 is free, but cross-AZ and cross-region traffic is chargeable.
- Private IPs are cheaper than Public IPs.
- Use the same AZ to save costs (but at the expense of availability).
- Egress traffic (outbound) is chargeable.
- AWS Direct Connect: Choose co-located regions for lower egress costs.
- S3 Cost Optimization:
- Inbound traffic is free, outbound (egress) is paid.
- CloudFront -> S3 is free.
- CloudFront from the internet is paid (but 7x cheaper due to caching).
- Cross-region traffic costs extra (2 cents per GB).
- Use VPC Endpoints instead of NAT Gateway to save costs.
AWS Network Protection & Security 🔒
- Network Access Control Lists (NACLs).
- Security Groups (stateful firewall for EC2 instances).
- AWS WAF (Layer 7 protection).
- AWS Shield & Shield Advanced (DDoS protection).
- AWS Firewall Manager (centralized rule management across accounts).
- AWS Network Firewall:
- Protects entire VPC (Layers 3 to 7).
- Monitors traffic between VPCs, to/from the internet, Direct Connect, and VPNs.
- Provides fine-grained control (IP/port filtering, protocol filtering, regex-based rules, etc.).
- Supports flow inspection and logging (S3, CloudWatch, Firehose).
- Eliminates the need for third-party firewall appliances.
TL;DR 🎯
- VPC Peering: Connects VPCs privately but is not transitive.
- VPC Endpoints: Private access to AWS services (use Gateway Endpoint for S3, Interface Endpoint for other services).
- Site-to-Site VPN: Connects on-premises to AWS (requires VGW, CGW, and proper routing).
- AWS VPN Cloud: Low-cost hub-and-spoke model for multiple VPN connections.
- Direct Connect: Dedicated private connection (higher speeds, lower latency, better security).
- Transit Gateway: Scales multi-VPC and on-premises networking (regional hub, supports cross-region peering).
- Traffic Mirroring: Captures and inspects VPC network traffic.
- Networking Costs: Use private IPs, same-AZ traffic, and VPC endpoints to save money.
- Network Security: Use AWS WAF, Shield, Firewall Manager, and Network Firewall for protection.
AWS networking can seem overwhelming, but once you understand these core concepts, building secure and cost-effective architectures becomes much easier! 🚀