>[!quote] In a Nutshell .Unique, hardcoded identifier for a device in a network. --- Every network device (such as a computer, smartphone, router, or switch) is assigned a **unique MAC address** by the manufacturer. Address is hardcoded into the devices hardware (NIC - network interface controller). The format is a $12$-digit hexadecimal number, separated by colons or hyphens ``` 00:14:22:01:23:45 00-14-22-01-23-45 ``` The first three bytes (24 bits) of the MAC address represent the **Organizationally Unique Identifier (OUI)**, which is assigned to the manufacturer of the device. The remaining three bytes are used to uniquely identify the specific NIC. --- #### Randomized MAC Address Some devices (e.g., smartphones and laptops) implement **MAC address randomization** for Wi-Fi connections, where a random MAC address is used when connecting to different networks to prevent the device from being tracked by its permanent MAC address.