VPC Peering
A networking connection between two VPCs that enables you to route traffic between them using private IPv4 or IPv6 addresses.
The Prerequisites
Two Target VPCs
Can be in the same or different accounts, and even different regions.
Non-Overlapping CIDRs
The IP address ranges of both VPCs must not overlap for routing to function.
Route Table Access
Permissions to modify route tables in both VPCs to direct traffic.
Security Group Logic
Ability to reference peer security groups (if in the same region).
The Connection Lifecycle
Establishing a secure tunnel between isolated networks
1
Request
VPC A sends a request to VPC B for peering.
2
Accept
Owner of VPC B accepts the request to form connection.
3
Route
Update Route Tables in both VPCs to point to pcx-id.
4
Secure
Modify Security Groups to allow inbound/outbound traffic.