What is a MAC address, and how is it different from an IP address?¶
title: "What is a MAC address, and how is it different from an IP address?" status: "complete" source_document: "https://docs.google.com/document/d/1GEIHVa5SkOVKwMs2mWwLMXuvG5IqCmUzf-NIxsc0axw/edit?usp=drivesdk"
What is a MAC address, and how is it different from an IP address?¶
A MAC address is an identifier used by a network interface when communicating on a local network.
MAC stands for Media Access Control. A MAC address is commonly written as six groups of hexadecimal characters, such as 00:1A:2B:3C:4D:5E, although other formats may be used.
An IP address and a MAC address perform different roles. An IP address supports communication between networks and may be visible to routers, providers and online services. A MAC address is principally used within the local network segment. It doesn't normally travel through the internet to a remote website or platform.
Local-network records may associate a MAC address with useful events. A Wi-Fi controller might record it when a device connects. A DHCP service may show that the interface using that MAC address received a particular private IP address. Network-access systems may connect it with an account, access point or device-registration record.
That can help distinguish locally connected interfaces, but a MAC address isn't a permanent serial number for a physical device. A device may have separate MAC addresses for Wi-Fi, Ethernet and other interfaces. Modern operating systems may also generate randomised or private MAC addresses, particularly when joining Wi-Fi networks.
MAC addresses can be changed, copied or falsely presented. Hardware may be replaced, virtual machines may use generated addresses, and several records may refer to different interfaces on the same device. Conversely, a deliberately copied address could make two devices appear under the same identifier at different times.
Interpret the address at the correct observation point. A MAC address recorded by a hotel Wi-Fi system may be useful within that network, but an external platform will normally record the public IP address through which the traffic reached it—not the device’s MAC address.
A MAC address can help connect a network interface with local connection records. It doesn't, by itself, identify the physical device with certainty, prove who was using it or establish responsibility for the activity.