Suggest an editImprove this articleRefine the answer for “What is a MAC address?”. Your changes go to moderation before they’re published.Approval requiredContentWhat you’re changing🇺🇸EN🇺🇦UAPreviewTitle (EN)Short answer (EN)**A MAC address (Media Access Control address)** is a unique hardware address of a network device, used at the data link layer (L2) to deliver data within a local network. **Key point:** a MAC address is unique worldwide because it consists of a manufacturer identifier (OUI) and a unique number assigned by the manufacturer.Shown above the full answer for quick recall.Answer (EN)Image**A MAC address (Media Access Control address)** is a **unique hardware address of a network device**, used **at the data link layer (L2)** to deliver data **within a local network**. Put simply: **A MAC address is the "physical address" of a network card**, by which devices find each other on the same network. --- ## Why a MAC address is needed A MAC address is needed to: - understand **who the frame is intended for** - deliver data **from one device to another within a LAN** - let the switch know **which port to send the frame to** Without MAC addresses the data link layer **could not deliver data by address**. --- ## What a MAC address looks like A MAC address is usually: - length: **48 bits (6 bytes)** - written in hexadecimal form Example: ``` 00:1A:2B:3C:4D:5E ``` or ``` 00-1A-2B-3C-4D-5E ``` --- ## What a MAC address consists of A MAC address is logically split into two parts: ### 1. **The first 3 bytes: the OUI** - the manufacturer identifier - shows **which company made the device** ### 2. **The last 3 bytes: a unique number** - assigned by the manufacturer - unique within that OUI As a result, a MAC address is **unique worldwide** (under normal circumstances). --- ## Where a MAC address is used A MAC address: - is used **in Ethernet and Wi-Fi frames** - works **only within a single local network** - **is not passed through routers** (each segment gets a new frame) --- ## Important points for an interview - A MAC address: - belongs to the **data link layer** - does not replace an IP address - MAC: - is used **for delivering frames** - IP is **for routing between networks** --- ## Can a MAC address be changed? Yes. - in software (MAC spoofing) - often used for testing, privacy, or bypassing restrictions But: - the **factory MAC address** is still "burned into" the device --- ## Simple analogy A house in a residential complex: - the MAC address is the apartment number - the IP address is the city's postal address --- ## Short version for an interview > **A MAC address** is a unique hardware address of a network interface, used at the data link layer to deliver frames between devices on a single local network.For the reviewerNote to the moderator (optional)Visible only to the moderator. Helps review go faster.