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What is a MAC Address?

A MAC address can be used to track and log your location, disrupt your connection, and even impersonate you on the network. But what is it, where can you find it — and what steps can you take to protect it? Here’s everything you need to know about your MAC address.

What is a MAC Address?

A Media Access Control (MAC) address is a string of characters that identifies a device on a network. It’s tied to a key connection device in your computer called the Network Interface Card, or NIC. The NIC is essentially a computer circuit card that makes it possible for your computer to connect to a network. A NIC turns data into an electrical signal that can be transmitted over the network.

Every NIC has a hardware address that’s known as a MAC address. Whereas IP addresses are associated with a networking software called TCP/IP, MAC addresses are linked to the hardware of network adapters.

Manufacturers assign a MAC address to a network adapter when it is produced. It is hardwired or hard-coded onto your computer’s NIC and is unique to it. Something called the Address Resolution Protocol (ARP) translates an IP address into a MAC address. Think of the ARP as a passport that takes data from an IP address through an actual piece of computer hardware.

mac address

How to find the MAC Address of a device

By now, you may be wondering how to find your device’s MAC address. If you have a Windows-based device, follow these steps:

  • Press the Windows key or click Window Start
  • You will get a search box. Type “cmd” to open your command prompt
  • Press Enter. Then type “ipconfig/all command” at the prompt and press Enter
  • You will get a screen with a lot of information displayed. Scroll down and look for the physical address. That’s your MAC address.

If you have a macOS system, follow these steps:

  • Open the Apple Menu and click on System Preferences, or just choose the Apple icon
  • Under system preferences → Select Network →
  • That path opens a network box
  • Select the Wi-Fi option found in the box. It then shows the Wi-Fi address or the Airport Address displays, and that’s where you will find your device’s MAC address

Types of MAC addresses

There are three types of MAC addresses:

  • Unicast MAC address. A unicast address is attached to a specific NIC on the local network. Therefore, this address is only used when a frame is sent from a single transmitting device to a single destination device.
  • Multicast MAC address. A source device can transmit a data frame to multiple devices by using a multicast A multicast group IP address is assigned to devices belonging to the multicast group.
  • Broadcast MAC address. This address represents every device on a given network. The purpose of a broadcast domain is to enable a source device to send data to every device on the network by using the broadcast address as the destination’s MAC address.

Why should the MAC Address be unique in a LAN Network?

The device may be identified both inside and outside of the LAN thanks to the MAC address, which is intended to be unique. When a switch broadcasts packets to all of its ports, only the MAC address determines which port the packet will reach at its destination (Address Resolution Protocol). Because of this, MAC addresses ought to be distinct. MAC addresses are likewise sent via the internet for the same single purpose. Within the Ethernet protocol that contains the MAC address is the TCP/IP protocol. The Ethernet protocol will be removed by the ISP’s(Internet service provider) hardware after it is finished.

Incoming packets will also have the Ethernet protocol removed by the modem before being forwarded to the router. The router will then re-encapsulate it and apply NAT before sending it to the switch and the required device.
A MAC address serves just to identify a specific network device, in this case, your modem in the case of an ISP.
They are special because it would be quite problematic to have two NICs with the same MAC address in the same network. On a network, multiple IP addresses are already causing issues for users. Consider the issues that arise from having multiple MAC addresses.

mac address

How is a MAC address different from an IP address?

Both MAC addresses and IP addresses are used to identify your device on a network but for different purposes.

Speaking in automobile terms, MAC addresses are like Vehicle Identification Numbers (VINs), which are unique to each vehicle. IP addresses are like license plates, which can be reassigned or transferred to different vehicles (VINs).

Whereas your computer (with MAC address X) may have an IP of 1.2.3.4 today if you were to remove your computer from the network, that IP address could then be used by your Roku (with MAC address Y).

MAC addresses are used to route data within the same local network. You need an IP address if you want your data to transfer to other networks, such as the Internet.

Characteristics of MAC Address

The Media Access Control address (MAC address) is a unique identifier assigned to most network adapters or network interface cards (NICs) by the manufacturer for identification and use in the Media Access Control protocol sub-layer.
An Ethernet MAC address is a 48-bit binary value expressed as 12 hexadecimal digits (4 bits per hexadecimal digit). MAC addresses are in a flat structure and thus they are not routable on the Internet. Serial interfaces do not use MAC addresses. It does NOT contain a network and host portion with the address. It is used to deliver the frame to the destination device.

  • MAC addresses are used in LAN (Local Area Network) environments to identify devices and allow communication between them.
  • MAC addresses are burned into the hardware of a network interface card (NIC) and cannot be changed, except in some rare cases where the manufacturer has provided a specific tool to do so.
  • The first 3 bytes of a MAC address represent the manufacturer ID, while the last 3 bytes represent a unique identifier assigned by the manufacturer.
  • MAC addresses are often used in conjunction with ARP (Address Resolution Protocol) to resolve IP addresses to MAC addresses for communication on a LAN.
  • Some operating systems, such as Windows and Linux, allow you to view the MAC address of your network adapter through a command prompt or network settings.

Conclusion

In this tutorial, we explored MAC addresses. First, we briefly reviewed the basic concepts and characteristics of MAC. So, we studied the formatting of MAC addresses and the purpose of the main fields of it. Finally, we investigated the differences and relations between MAC and IP addresses. We can conclude that MAC, with other protocols, bases modern networking. MAC addresses identify network devices, enabling them to communicate with each other in a local group or network by sending and receiving messages.

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