Layer 2 of OSI Model

Media Access Control (MAC)

IP Address changes. MAC does not change.

Switch needs MAC address to forward data.

Use ifconfig/all and look for “Physical Address”.

A Media Access Control (MAC) address is a unique identifier for network interface cards (NICs) used in devices. It operates at the Data Link Layer (Layer 2) of the OSI model and helps in directing data frames to specific devices within a local network.

A MAC address is usually expressed as a series of six pairs of alphanumeric characters separated by colons or hyphens, like


A MAC address, short for Media Access Control address, is a unique identifier assigned to a network interface controller (NIC) for communications within a local network segment. It serves as a way to identify devices on a local network and is crucial for protocols like Ethernet, Wi-Fi, and Bluetooth.

How are MAC addresses assigned?

MAC addresses are primarily assigned by device manufacturers, and are therefore often referred to as the burned-in address, or as an Ethernet hardware address, hardware address, or physical address. Each address can be stored in hardware, such as the card’s read-only memory, or by a firmware mechanism.

Can't you spoof the address then?

Yes, that is a very real possibility.

MAC vs. IP Addresses

I still don’t really get the differences. I don’t have a solid intuition of why. Like shouldn’t we just use MAC addresses for everything?

Why do we use MAC addresses over IP addresses?

MAC addresses are only used for communication on Local Area Networks (LANs), so if you want to access a remote network or the Internet, you need an IP address. StackOverflow


I saw that we add the MAC address to the whitelist. This way, even if you flash the computer, the MAC address doesn’t change, since that is embedded into the hardware through the Network Interface Card.