What is a MAC address?
A MAC address, for Media Access Control, is the address that physically, directly identifies your equipment, outside of any network. As with IP addresses, any equipment that can be connected to a network has a MAC address.
A MAC address is often represented in hexadecimal form as follows:
44:d1:fa:b8:97:f9
Comment fonctionne une adresse MAC?
This address consists of 6 bytes, (each byte containing 8 bits). Within these six bytes and 48 bits, 1 bit indicates if the address is individual, (its value will then be 0), or of group, (its value will then be 1). Then 1 bit indicates whether the address is universal by a 0, or local, i.e. administered locally, by a 1. Then 22 bits indicate the manufacturer's address and the remaining 24 bits indicate the equipment's address. This address is unique and therefore defined by the manufacturer of the equipment.
In addition, a device's MAC address is sometimes referred to as its physical address, as opposed to the IP address, which is its network address. The former is associated with the equipment itself, where the IP address is associated with the equipment's location in the network. We can make an analogy with your home for example. As with the MAC address of a device, your home has its own geographical location, described with a latitude and longitude; whether it is attached to a city, a country, or any other administrative organization, your home is located here on the planet. On the other hand, if your home is located in a city and a country, it has a postal address. A MAC address is therefore independent of the network in which your equipment is located in the same way that your home has geographical coordinates independent of any city or country.
What is the purpose of a MAC address?
The MAC address is used for several important tasks on a network. Here are some examples:
Identify network devices: The MAC address is used to identify each device connected to a network. This allows the switch to know which port each device is connected to.
Access Control: MAC address is used to restrict access to a network. Network administrators can configure access control lists (ACLs) to allow or deny access based on a device's MAC address.
Network Analysis: MAC address is used to monitor network traffic and detect performance problems. Network monitoring tools use the MAC address to identify active devices and measure traffic.
Where to find the MAC address?
Finally, as for the IP address, to know the MAC address of your equipment, you can use the Windows Command Prompt, (accessible with the cmd command in your windows search bar), and type the command: getmac/v, all in lower case.
You will then see the MAC address of your computer's network cards. Note that many devices simply have their MAC address written on the back.
Yohann CORNILLIERE
Project Manager Citypassenger
I manage internal and collaborative research projects as well as City-Academy training, including the organization of trainings and the creation of modules to explain network concepts.
