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VPC

  • Virtual Private Cloud
  • Multiple VPCs in single AWS region.
  • Only private IPv4 ranges are allowed.

Default VPC

  • All AWS accounts have a default VPC.
  • It has internet connectivity and all EC2 instances inside have public IPv4 addresses.

Subnet (IPv4)

  • AWS reserves 5 IP addresses in each subnet.

VPC Peering

  • Privately connect two VPCs using AWS network.
  • Must not have overlapping CIDRs.
  • Must update route tables in each VPC's subnets to ensure EC2 instances can communicate with each other.

VPC Endpoints

  • Allows to connect to AWS services using a private network instead of using the public internet.

Types of Endpoints

  • Interface Endpoints: Provisions ENI as an entry point.

  • Gateway Endpoints: Provisions a gateway and must be used as a target in route table; only supports S3 and DynamoDB.

VPC Flow Logs

  • Capture information about IP traffic going into interfaces.
  • Captures network information from AWS managed interfaces too.

Architectures

Traffic Mirroring

  • Capture and inspect network traffic.
  • Route the traffic to security appliances that you manage.

IPv6 in VPC

  • IPv4 cannot be disabled for VPC and subnets.
  • Can enable IPv6 to operate in dual-stack mode.