Which component connects two VPCs to allow communication as if in the same network?

Which component connects two VPCs to allow communication as if in the same network?

• A. NAT gateway
• B. VPN
• C. VPC peering
• D. Transit gateway

Answer: (C)

Connecting two VPCs so they can communicate as if they’re in the same network is achieved with a VPC peering connection. It creates a private, direct link between the two VPCs so resources can reach each other using their private IP addresses without ever going over the public internet. Traffic stays on AWS’s network, and you control access with security groups and network ACLs. To make this work, each VPC’s route table must include a route for the other VPC’s CIDR block that directs traffic to the peering connection. Remember that the VPC CIDR blocks must not overlap, and this setup isn’t transitive—traffic from one VPC to another can’t automatically hop through a third VPC via peering. NAT gateway isn’t for connecting two VPCs; it enables instances in a private subnet to access the internet. VPN can connect networks through encrypted tunnels (including VPC-to-VPC connections), but it adds complexity and overhead and isn’t the simplest way to make two VPCs behave like one network. Transit gateway can connect many VPCs through a central hub, which is more scalable when you have multiple VPCs, but for a direct two-VPC connection, VPC peering is the straightforward choice.

Connecting two VPCs so they can communicate as if they’re in the same network is achieved with a VPC peering connection. It creates a private, direct link between the two VPCs so resources can reach each other using their private IP addresses without ever going over the public internet. Traffic stays on AWS’s network, and you control access with security groups and network ACLs. To make this work, each VPC’s route table must include a route for the other VPC’s CIDR block that directs traffic to the peering connection. Remember that the VPC CIDR blocks must not overlap, and this setup isn’t transitive—traffic from one VPC to another can’t automatically hop through a third VPC via peering.

NAT gateway isn’t for connecting two VPCs; it enables instances in a private subnet to access the internet. VPN can connect networks through encrypted tunnels (including VPC-to-VPC connections), but it adds complexity and overhead and isn’t the simplest way to make two VPCs behave like one network. Transit gateway can connect many VPCs through a central hub, which is more scalable when you have multiple VPCs, but for a direct two-VPC connection, VPC peering is the straightforward choice.