gen-briefly-explain-ip-addressing-and-subnetting-and-one-common-0919

Briefly explain IP addressing and subnetting and one common misconception about it.

# IP Addressing and Subnetting **IP Addressing** is a system for uniquely identifying devices on a network. An IPv4 address consists of 32 bits, typically written as four decimal numbers (0-255) separated by dots, like `192.168.1.100`. **Subnetting** is the practice of dividing a larger network into smaller sub-networks. This is done using a subnet mask (like `255.255.255.0` or `/24` notation), which determines which portion of an IP address identifies the network and which identifies individual hosts. For example: - IP: `192.168.1.100/24` - The `/24` means the first 24 bits identify the network - This leaves 8 bits for hosts (256 addresses, though 2 are reserved) ## Common Misconception **"The last octet in a subnet can use all 256 addresses (0-255) for hosts"** In reality, **two addresses are always reserved**: - The **network address** (all host bits = 0, e.g., `192.168.1.0`) - The **broadcast address** (all host bits = 1, e.g., `192.168.1.255`) So a `/24` subnet actually provides 254 usable host addresses, not 256. Many beginners overlook this when planning network capacity.