CIDR (Classless Inter-Domain Routing) is a method for allocating and specifying network addresses on the internet. It uses a slash
notation (e.g., /24) to indicate the number of network bits in an IP address, determining the size of the network.
Analogy: Think of CIDR like zip codes, where a shorter code (e.g., 90210) covers a smaller area than a longer code (e.g., 90210-1234).
Why It Matters: CIDR allows for efficient allocation of IP addresses and is fundamental to configuring networks in AWS, defining the address space for VPCs and subnets.