Скачать или смотреть Notebookin w/ Mindy #84 (The IP Address Puzzle)

The Three Types of Addresses
+ Subnet Address (First Address): acts like a "Street Name." It refers to the entire network or street rather than a specific location. It is always the very first address in a block.
+ Broadcast Address (Last Address): Acts like a "Town Crier." It is used to send a message to every device on that network. It is always the very last address in a block
+ Host Addresses (Middle Addresses): Act like "House Numbers." These are the usable addresses assigned to specific devices (laptops, phones, consoles)

The "Magic Key": CIDR Notation
To determine the type of address, you need to calculate the block size using the slash number (CIDR notation) at the end of the IP

The Math Formula
1. Subtract the slash number from 32 (since IPv4 addresses are 32 bits).
Formula: 32 - {Slash Number} = n
2. Calculate 2 to the power of that result.
Formula: 2^n = {Block Size}

Example 1: 192.168.2.32/27
Math: 32 - 27 = 5. Then 2^5 = 32. The block size is 32.
Logic: Subnet starting points must be multiples of the block size (0, 32, 64, 96, etc.).
Result: Since 32 lands exactly on a multiple, this is a Subnet Address

Example 2: 192.168.2.32/26
Math: 32 - 26 = 6. Then 2^6 = 64$. The block size is 64.
Logic: Subnet starting points are multiples of 64 (0, 64, 128...). The range for the first block is 0 to 63.
Result: 32 does not land on a start point (0 or 64) nor is it the last address (63). It falls in the middle, making it a Host Address

Quick Tips
Total Usable Hosts: The number of usable addresses is always the total block size minus 2 (one for the subnet, one for the broadcast)
Validation: If an address lands on the start of a block multiple, it's a Subnet. If it is one less than the next block start, it's a Broadcast. Otherwise, it is a Host.