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A MAC address(엠카주소) is unique and hardcoded into a device when it’s manufactured. It operates on the data link layer of the OSI model.
Media Access Control (MAC) address
MAC addresses are unique 48-bit serial numbers that identify network adapter hardware. They are used by the physical layer to differentiate devices on a local area network (LAN). They are also known as the “brick” address because they’re burned into the NIC (network interface card) during manufacturing. Unlike IP addresses, which are assigned by software, MAC addresses are uniquely associated with the hardware of the NIC and can’t be changed.
A MAC address is unique to every device connected to the same network, which can be either wired or wireless. During the networking process, each device sends frames that contain a MAC address to other devices. This helps them find the destination of the frame. In addition, each NIC has a built-in filter that identifies MAC addresses, preventing malicious users from accessing the network.
In the OSI model, MAC addresses are considered part of the physical layer. It is the lowest level of the data link layer that enables upper-layer protocols to produce complex networks. The MAC layer controls the transmission of information from one NIC to another over the physical media, such as copper wires or radio frequencies.
The MAC address is also used to distinguish between individual or group addresses. It is the first three octets of a MAC address that identify the manufacturer, which are known as the Organizationally Unique Identifier (OUI). The last octets can be assigned by the organization or vendor to each NIC, which is called a Functional Address. If the least significant bit is set to 1, a device has a group address, and packets sent to this address are received by all NICs within the same functional group. In some cases, this group could be a single network segment. However, in the majority of cases, the groups are defined by functional specifications, which determine which NICs should receive each packet. The MAC layer is also responsible for error checking, frame retransmission, and broadcast control.
MAC address hexadecimal
A MAC address is a unique identifier for networking hardware, such as a network card in your computer or a wireless router. The MAC address is assigned by the manufacturer and never changes, even when you change hardware or connect to a new Wi-Fi or Bluetooth network. A MAC address can be converted to decimal, binary or hexadecimal numbers. The hexadecimal representation is more intuitive for humans to read since we use the base sixteen number system (sixteen digits plus leading zeroes). A MAC address consists of six bytes, or 12 hexadecimal digits, that represent 48 bits. Bits are grouped into groups of eight, which are called bytes in computer-speak. Two hexadecimal digits are equivalent to one byte, so a MAC address is represented as a series of eight bytes separated by colons.
The first six hexadecimal digits in a MAC address identify the manufacturer, also known as an Organizationally Unique Identifier (OUI). The IEEE administers manufacturers’ OUIs. Some vendors have more than one OUI, and this can cause confusion if two pieces of hardware from different manufacturers have the same OUI.
An IP address identifies software, while a MAC address identifies the hardware in a network. The two work together to communicate with each other and share information on the data link layer of a network. The MAC address is also sometimes referred to as the Ethernet hardware address, burned-in address, or physical address.
To find a MAC address in your computer, open the Terminal application from Utilities or Command + Shift + T. Then, type ifconfig and press Enter. The output should list all of the current networks and their MAC addresses. The MAC address that appears last in the list is your computer’s. If this address is not listed, you will have to use a utility that displays hidden network information, such as NetworkInformation. Once you have found the MAC address, you can write it down for reference.
