What is MAC address

Every device on the internet has two addresses; one of them is MAC address and another one is IP address. Both of them are important for sending data over the internet but the uses of them are different. In this article, we are going to explain MAC address.

We try to find the answers of “What is MAC address?”, “What does it do?”, “Why do we use it and more”.

What is MAC address?

MAC address is short form of medium access control address or media access control address. This protocol is a unique identifier assigned to a network.

Interface controller (NIC) uses as a network address for communications within a network segment. Uses as a communications is common in most IEEE 802 networking technologies, including Ethernet, Wi-Fi, and Bluetooth.

Within the Open Systems Interconnection (OSI) network model, MAC addresses are used in the medium access control protocol sublayer of the data link layer.

As typically represented, MAC addresses are recognizable as six groups of two hexadecimal digits, separated by hyphens, colons, or without a separator. A MAC address is required when trying to locate a device or when performing diagnostics on a network device.

The MAC address belongs to the data link layer of the Open Systems Interconnection (OSI) model, which encapsulates the MAC address of the source and destination in the header of each data frame to ensure node-to-node communication. MAC Address is worldwide unique since millions of network devices exist and we need to uniquely identify each.

What are the uses of MAC addresses?

All devices on the same network subnet have different MAC addresses. MAC addresses are very useful in diagnosing network issues such as problems with IP addresses.

MAC addresses are useful for network diagnosis because they never change. For a network administrator, that makes a MAC address a more reliable way to identify senders and receivers of data on the network.

On wireless networks, a process called MAC filtering is a security measure to prevent unwanted network access by hackers and intruders. In MAC address filtering, the router is configured to accept traffic only from specific MAC addresses.

This way, computers whose MAC addresses are approved will be able to communicate through the network — even if they were given a new IP address by the Dynamic Host Configuration Protocol (DHCP) process.

Meanwhile, a hacker who’s hijacked a network IP address will be blocked because their MAC address will not be on the approved list and will be filtered out.

What is the Format of MAC Address?

For understanding better what is MAC address, you must know it is very important that first you understand the format of the MAC Address. So a MAC Address is a 12-digit hexadecimal number (48-bit binary number), which is mostly represented by Colon-Hexadecimal notation.

The First 6 digits (say 00:40:96) of the MAC Address identify the manufacturer, called the OUI (Organizational Unique Identifier). IEEE Registration Authority Committee assigns these MAC prefixes to its registered vendors.

Here are some OUI of well-known manufacturers:

CC:46:D6 – Cisco
3C:5A:B4 – Google, Inc.
3C:D9:2B – Hewlett Packard
00:9A:CD – HUAWEI TECHNOLOGIES CO.,LTD

The rightmost six digits represent Network Interface Controller, which is assigned by the manufacturer. As discussed above, the MAC address is represented by Colon-Hexadecimal notation. But this is just a conversion, not mandatory.

MAC address can be represented using any of the following formats:

Different types of MAC address:

Unicast: A Unicast-addressed frame is only sent out to the interface leading to a specific NIC. If the LSB (least significant bit) of the first octet of an address is set to zero, the frame is meant to reach only one receiving NIC.

The MAC Address of the source machine is always Unicast. 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.

2. Multicast: The multicast address allows the source to send a frame to a group of devices. In Layer-2 (Ethernet) Multicast address, the LSB (least significant bit) of the first octet of an address is set to one. IEEE has allocated the address block 01-80-C2-xx-xx-xx (01-80-C2-00-00-00 to 01-80-C2-FF-FF-FF) for group addresses for use by standard protocols. 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.

3. Broadcast: Similar to Network Layer, Broadcast is also possible on the underlying layer (Data Link Layer). Ethernet frames with ones in all bits of the destination address (FF-FF-FF-FF-FF-FF) are referred to as the broadcast addresses. Frames that are destined with MAC address FF-FF-FF-FF-FF-FF will reach every computer belonging to that LAN segment. 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.

How to find the MAC address?

A MAC address is mostly used to configure a router for a network device or during troubleshooting. The address of our computer device can be easily checked with any operating device. All the Apple devices connected to our home network contain a unique MAC address. Manufacturers may identify a MAC address by other names, such as the physical address, hardware ID, wireless ID, and Wi-Fi address.

Following are the steps which help to find MAC addresses for different OS.

• Windows:

Command: ipconfig / all

Step1: press windows start or click on windows key.

Step2: in the search box, type cmd and the command prompt will get open.

Step3: click on cmd, the command prompt window will display.

Step 4: in the command prompt type ipconfig/all command and then press enter.

Step5: as you will scroll down, every physical address is the MAC address of your device,

• MacOS:

Command: TCP/IP control panel

Step1: click on system setting.

Step2: in the system settings, click on the MAC network option.

Step3: then go to the advanced settings.

Step4: here you id your MAC address.

• Unix/Linux:

Command:

ifconfig-a

Ip link list

Ip address show

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• iPhone

step1: Go to the Settings app.

Step2: Select General, and click on About.

Step3: The wireless MAC address is listed next to the Wi-Fi Address.

• Android

The specific instructions for finding the MAC address of an Android device might vary by manufacturer, but the following are general steps:

Step1: Open the Settings app.

Step2: Select About Phone/Tablet > Status.

Step3: The MAC address appears under Wi-Fi MAC address.

Read more: What is cisco router

What is difference between MAC address and IP address?

Both MAC addresses and IP addresses serve the same purpose, which is to identify a device on a network. While the MAC address identifies the physical address of a device on the same local network, the IP address identifies the device globally or through its internet address.

Why should the MAC address be unique in the LAN network?

If a LAN network has two or more devices with the same MAC address, that network will not work. Suppose three devices A, B, and C are connected to a network through a switch.

The MAC addresses of these devices are 11000ABB28FC, 00000ABB28FC, and 00000ABB28FC, respectively. The NIC of devices B and C have the same MAC address. If device A sends a data frame to the address 00000ABB28FC, the switch will fail to deliver this frame to the destination, as it has two recipients of this data frame.

Conclusion:

In this article we try to explain the MAC address and its uses. we hope, this post will be useful. if you want to know about network equipment and protocols of it, read our other blogs in Atech blog.