Amazon VPC - Main Components

• Region – Geographical area containing multiple Availability Zones (AZs).

• Availability Zone (AZ) – One or more discrete data centers within a region, with independent power, networking, and connectivity.

• VPC – The main container for all networking resources in AWS.

Networking

• Public Subnet – Has a route to an Internet Gateway, allowing direct internet access.

• Private Subnet – No direct route to the internet, typically for internal-only resources.

Connectivity

• Internet Gateway (IGW) – Enables internet access for resources in public subnets.

• NAT Gateway – Allows outbound internet traffic from private subnets while blocking inbound connections.

• Router – Handles routing between subnets and external networks.

• Route Table – Contains routing rules defining how traffic is directed.

Security

• Security Group (SG) – Stateful firewall at the instance level; remembers allowed connections and applies rules to both inbound and outbound traffic.

• Network ACL (NACL) – Stateless firewall at the subnet level; requires explicit rules for both inbound and outbound traffic.

Compute

• Public EC2 Instance – EC2 launched in a public subnet with internet access.

• Private EC2 Instance – EC2 launched in a private subnet without direct internet access.

Monitoring & Logging

• VPC Flow Logs – Capture IP traffic details for network interfaces, subnets, or the VPC.

• CloudWatch – Monitors and visualizes metrics and logs.

Additional Services

• S3 – Can be accessed via an Internet Gateway or through a VPC Endpoint (PrivateLink).

• DynamoDB – Can be accessed via an Internet Gateway or through a VPC Endpoint.

Hybrid Connectivity

• Customer Gateway (CGW) – Represents your on-premises network device or software for VPN/DX.

• VPN Gateway (VGW) – AWS side of a VPN connection.

• Site-to-Site VPN – Encrypted connection between on-premises and AWS VPC.

• Direct Connect (DX) – Dedicated physical network connection from your premises to AWS.

• DX Location – AWS facility where your Direct Connect connection terminates.

VPC Peering & Transit

• VPC Peering – Direct networking link between two VPCs.

• Transit Gateway (TGW) – Centralized hub for connecting multiple VPCs and on-premises networks.