Programmer: "Congratulations on the new daughter. Have you picked a name yet?"
Me: "Not yet — she only has a MAC address." 🙄 😝
What Is a MAC Address?
A MAC address, also known as a "Physical Address," is a 48-bit identifier assigned to every network card manufactured today.
Much like your national ID number, a MAC address is unique to each network card and cannot be shared between different cards.
The first half of the address is a manufacturer identifier. Each manufacturer is assigned a unique ID by the international standards organization (IEEE), while the second half identifies the specific network card.
MAC addresses are primarily used for communication on a local area network. If your office has ten computers exchanging data through a switch, the MAC address is what identifies the sender and the recipient.
MAC addresses also play a role in information security. For example, you can create a whitelist that restricts network access to only those network cards with specific MAC addresses. To bypass such a protection, hackers will "spoof" a MAC address in order to impersonate another device.
One interesting and lesser-known use that I encounter almost every day is the activation of OEM Windows licenses.
These licenses are tied to the MAC address of the network card, which means that even after a fresh installation of the operating system, the license is still activated automatically. On the flip side — replacing the motherboard, including its network card, will cause the license to stop working.
Image Source: Wikipedia