> For the complete documentation index, see [llms.txt](https://docs.ipcheck.ing/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ipcheck.ing/knowledge-base/lookup-privacy/mac-lookup.md). # MAC Lookup ## What a MAC address is A MAC address is the hardware identifier of a network interface. Every Wi-Fi radio, Ethernet port and Bluetooth chip has one. It is 48 bits long, written as 12 hexadecimal digits, usually in pairs separated by colons — for example `F0:2F:4B:01:0A:AA`. The first half of the address is assigned to a manufacturer by the IEEE. The second half is chosen by that manufacturer for each device it builds. That is why a MAC address can often tell you who made a device. Unlike an IP address, a MAC address is only visible inside your local network. It does not travel across the internet. ## How to run it {% stepper %} {% step %} ### Open the tool Go to **Advanced Tools** and click the **MAC Lookup** card, or open `/tools/macchecker` directly. {% endstep %} {% step %} ### Enter the address Type the full address and press Enter, or click the search button. {% endstep %} {% endstepper %} ### Accepted input formats The tool needs all 12 hexadecimal digits. Separators are optional, and you may use colons or hyphens: | Format | Example | Accepted | | ---------------------------- | ------------------- | -------- | | Colon-separated | `F0:2F:4B:01:0A:AA` | Yes | | Hyphen-separated | `F0-2F-4B-01-0A-AA` | Yes | | No separators | `F02F4B010AAA` | Yes | | Upper or lower case | `f0:2f:4b:01:0a:aa` | Yes | | Only the first six digits | `F0:2F:4B` | No | | Dot-separated groups of four | `f02f.4b01.0aaa` | No | If the input is not exactly 12 hex digits after separators are removed, you get **Invalid physical address**. ## Reading your results The result has two parts. ### Manufacturer details | Field | What it means | | ------------------------------- | ---------------------------------------------------------------------------------- | | **Physical address prefix** | The part of the address that identifies the manufacturer. | | **Start block** / **End block** | The first and last address in the range assigned to that manufacturer. | | **Block size** | How many addresses that range contains. | | **Block type** | The kind of IEEE assignment, for example a large `MA-L` block or a smaller `MA-S`. | | **Manufacturer** | The company the block is registered to. | | **Registered country/region** | The country in the IEEE registration, shown with a flag. | | **Registered address** | The postal address on file with the IEEE. | ### Address property A short list of yes/no properties, marked with a tick or a cross: | Property | What it means | | --------------------- | -------------------------------------------------------------------------------- | | **Random address** | The address looks randomised rather than factory-assigned. | | **Private data** | The manufacturer chose to keep its registration details private. | | **Multicast address** | Traffic is meant for a group of devices. | | **Unicast address** | Traffic is meant for one device. This is the normal case. | | **Global address** | Globally administered, so it came from an IEEE-assigned block. | | **Local address** | Locally administered, so it was set by software rather than by the manufacturer. | Unicast and multicast are opposites, and so are global and local. Exactly one of each pair will be ticked. ## Limits worth knowing {% hint style="warning" %} A vendor lookup is a good hint, not proof of what a device is. {% endhint %} * **Modern phones and laptops randomise their MAC address.** iOS, Android, Windows and macOS all generate a new private address per Wi-Fi network by default, specifically to stop networks tracking you. Such an address is locally administered, so it shows as **Local address** and often as **Random address**, and there is no manufacturer to look up. * **The manufacturer is the chip maker, not the brand.** Many devices use network chips from a handful of suppliers, so the name you get may not match the logo on the box. * **Registrations go stale.** Blocks change hands and companies are renamed, so the registered address can be years out of date. * **A MAC address can be changed in software.** Treat it as an identifier, not as an authentication. ## Typical uses * **An unknown device is on your router.** Copy its MAC address from your router's client list and look it up. Knowing it is a printer, a TV or a smart plug is often enough to identify it. * **Confirm a device before you block it.** Check the vendor matches the device you intend to remove. * **Check an address you generated yourself.** If you set a custom MAC, the property list confirms it is unicast and locally administered. ## What to do next * Understand the difference between local and public addressing in [Public, Private & CGNAT Addresses](/knowledge-base/concepts/public-private-cgnat.md). * Want to know about the addresses that *are* visible on the internet? See [IP Information](/knowledge-base/connection-tools/ip-information.md). * Reduce what your devices reveal on networks you join with the [Security Checklist](/knowledge-base/lookup-privacy/security-checklist.md). --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. 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