VPC Routing

Basics

• Route tables for your VPC

CIDR-Overlap

• Peering between overlapping CIDRs isn't supported
• Create routes specific to subnets in VPCs with same CIDR

• Single route table solution

  • Add a more specific route for VPC-Y with CIDR from VPC-Y

• Different route tables solution

  • one route table for subnet-X in VPC-I routing to VPC-X
  • another route table to subnet-Y in VPC-I routing to VPC-Y
  • A solution but not a HA solution

Ingress routing

• Gateway route tables can be used to direct a gateway (e.g. IGW) to take actions in inbound traffic - such as forwarding it to a security appliance
• fine-grain control over the routing path of traffic entering your VPC.