Route tables

Every subnet must define a route table that defines how to route traffic within that subnet. A route table consists of one or more routes, where each route specifies a destination, which is the range of IP addresses (in CIDR notation) to route, and the target, which is where to send the traffic for that range of IP addresses.

Here’s an example route table:

Destination	Target
10.0.0.0/24	Local
0.0.0.0/0	igw-12345

This route table sends all traffic within the subnet’s CIDR block, 10.0.0.0/24, to the Local route, which means it will be automatically routed within the subnet by AWS. This table then adds a fallback route for all other IPs (0.0.0.0/0) to send traffic to the an Internet Gateway with ID igw-12345. We’ll discuss Internet Gateways next.