What is a MAC Address: How to Find and Identify

Whether you work in a wired network office or a wireless one, one thing is common for both environments: It takes network software and hardware (cables, routers, etc.) to transfer data from your computer to another, or from a computer thousands of miles away to yours. In the end, to get the data you want right to YOU, it comes down to addresses — specifically, IP addresses and MAC addresses. 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. 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, as opposed to a dynamic IP address, which can change from time to time. 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. Some well-known manufacturers of network adapters or NICs are Dell, Belkin, Nortel, and Cisco. These manufacturers all place a special number sequence (called the Organizationally Unique Identifier or OUI) in the MAC address that identifies them as the manufacturer. The OUI is typically right at the front of the address. For example, consider a network adapter with the MAC address “00-14-22-01-23-45.” The OUI for the manufacture of this router is the first three octets: 00-14-22. Note that in computer-speak, an octet means a set of 8 bits. Two hexadecimal digits represent 8 bits and thus one octet. The OUIs for some well-known manufacturers are: It’s common for the larger manufacturers of networking equipment to have more than one set of OUIs. The basic difference between an IP address and a MAC address is that an IP address represents software and a MAC address represents hardware. The MAC address identifies specific devices within the same local network and the IP address identifies those devices outside of the local network. Once again, that’s hardware and software working together, IP addresses and MAC addresses working together. The MAC address is sometimes referred to as a networking hardware address, the burned-in address (BIA), or the physical address. An example of a MAC address for an Ethernet NIC would be: 00:0a:95:9d:68:16. As you’ve probably noticed, the MAC address itself doesn’t look anything like an IP address (see yours here ). The MAC address is a string of usually six sets of two-digits or characters, separated by colons. There are two ways to find your MAC address on Windows 10: with the command prompt and in network settings . Follow these steps to find the MAC address on your Mac computer: Since machines running Linux can have a variety of distributions with different settings formats, the easiest way to find the MAC address on Linux is by using the command prompt. Follow these steps to find the MAC address for your iOS device: The instructions for finding the MAC address of an Android device differ slightly depending on the device. In general, however, the process should resemble the following steps: Note that some Android devices have a privacy feature that assigns the device a randomized MAC address, rather than using the device’s real MAC address. A MAC address is one of those crucial things you have to have if you want to connect to the internet but that you won’t need to think about most of the time. But if you’re trying to configure a router or administer a network, you’ll want to know how to find them. Using a randomized MAC address enhances privacy by hiding the device’s real MAC from networks, which reduces tracking. However, it may cause connection issues on some networks that require a specific device MAC for access. A randomized MAC address helps protect your privacy by making it harder for networks to track your device across multiple connections, reducing targeted tracking. MAC spoofing allows attackers to disguise their device as another to: This can lead to compromised security and privacy on the network.