Understanding IPv4 addresses and the technique of dividing networks.
An Internet Protocol (IP) address is a unique numerical label assigned to each device connected to a computer network that uses the IP for communication. It serves two main functions: host identification and location addressing. The most common version is IPv4, which uses a 32-bit address, typically written as four decimal numbers separated by dots (e.g., 192.168.1.1). A 32-bit address space allows for approximately 4.3 billion unique addresses. Each IP address is divided into two parts: the network portion and the host portion. The network portion identifies the specific network the device is on, while the host portion identifies the specific device on that network. To distinguish these two parts, a subnet mask is used. For example, a subnet mask of 255.255.255.0 indicates that the first three octets are the network portion. Subnetting is the process of taking a single large network and breaking it down into multiple smaller subnetworks, or subnets. This is done by 'borrowing' bits from the host portion of the address to create a subnet identifier. Subnetting is essential for several reasons. It allows for more efficient use of the IP address space. It improves network security by containing traffic within a subnet. It also improves performance by reducing the size of the broadcast domain, as broadcasts are generally confined to their local subnet. Learning to calculate subnet masks, network addresses, broadcast addresses, and the range of usable host IPs for a given subnet is a critical skill in networking.