What is subnets?

A subnet (short for subnetwork) is a smaller part of a network. Think of it like dividing a big house into rooms. Each room (subnet) is part of the same house (network), but it serves a specific purpose and has its own boundaries.

In the context of AWS VPC:

  • A VPC is your private network in the cloud.
  • Subnets are sections of that private network.

Why use subnets?

  1. Organization: You can divide your network into smaller sections for different types of resources. For example:
    • One subnet for your web servers (accessible from the internet).
    • Another subnet for your database servers (private and not accessible from the internet).
  2. Control: Subnets help you control who can access what. You can decide if a subnet is public (can connect to the internet) or private (cannot directly connect to the internet).
  3. Scalability: Breaking a network into subnets makes it easier to manage and grow without mixing up everything.

Example:

Imagine you have a company with:

  • A public-facing website (web servers).
  • A database that stores sensitive information.

You could:

  • Create a public subnet for your web servers (so they can talk to users on the internet).
  • Create a private subnet for your database (so only the web servers can talk to it, not the internet).

Subnets are like creating rooms in a building with locks and rules about who can enter each room.4o