Final answer:
Route tables in VPCs are essential for network traffic direction, determining how data packets travel within the VPC, to the internet, or other VPCs. Each VPC subnet must be associated with a route table that can contain various routes, including private subnets without internet access and configurations for VPC peering.
Step-by-step explanation:
What is true of Route Tables and VPC subnets?
In the context of Virtual Private Clouds (VPC), route tables are critical components that determine how network traffic is directed within the VPC and to external networks. Each subnet within a VPC must be associated with a route table, which contains a set of rules, known as routes, that define the paths for traffic. These route tables ensure that data packets are directed to the correct destinations, whether inside the same network (intra-VPC) or outside of it (internet or other VPCs).
For instance, if you have a subnet that requires access to the internet, your route table will include a route that directs internet-bound traffic to a gateway. It's also possible to design a private subnet that does not have a route to the internet, often done for security or compliance reasons. Additionally, one can create more complex routing strategies such as VPC peering, where a route in a subnet's route table can direct traffic to a different VPC.
It is key to note that every VPC comes with a main route table, which can be overruled by custom route tables if specified. Route tables can be modified to change traffic routes as network requirements evolve, making the diligent design and management of route tables a crucial part of VPC networking.