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Networking Overview ​

Summary ​

  • AWS networking fundamentals center around VPC, subnets, route tables, Internet/NAT Gateways, Security Groups, and Network ACLs.
  • These components define how resources communicate within AWS, with on‑premises, and with the public internet, and are core to security and availability.
  • A solid grasp of VPC networking is essential before designing production architectures or taking most AWS certifications.

Networking landscape (mindmap) ​

mermaid
mindmap
  root((AWS Networking))
    VPC
      CIDR blocks
      Subnets
      Route tables
    Connectivity
      Internet Gateway
      NAT Gateway
      VPC Peering
      Transit Gateway
      VPN & Direct Connect
    Security
      Security Groups
      Network ACLs
    Edge
      CloudFront
      Route 53

Best Practices ​

  • Design VPCs and subnets explicitly (CIDR planning, public vs private subnets) instead of relying on the default VPC for production workloads.
  • Use Security Groups as the primary firewall, keeping rules least‑privilege and referencing other Security Groups rather than wide CIDR ranges.
  • Use Network ACLs as a stateless, subnet‑level guardrail for extra protection in sensitive environments.
  • For outbound‑only internet from private subnets, use NAT Gateways; expose only load balancers/bastion hosts in public subnets.
  • Centralize or simplify inter‑VPC connectivity using VPC Peering or Transit Gateway, especially in multi‑account environments.

Exam Notes ​

  • Be ready to distinguish Security Groups (stateful, instance/ENI‑level) from NACLs (stateless, subnet‑level) and choose the right one per scenario.
  • Understand typical patterns: public subnet + IGW for internet‑facing resources, private subnets + NAT for app/DB tiers, VPN/Direct Connect for hybrid connectivity.
  • Expect questions that hide networking issues behind symptoms (no internet, cannot connect between instances, high latency) where the fix is in SG/NACL/route table configuration.

AWS documentation ​