MAC-adresseopslag
Den første halvdel af en MAC-adresse angiver den organisation, blokken er registreret til. Slås op i vores kopi af IEEE-registret.
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A MAC address (for example 00:1A:2B:3C:4D:5E) identifies a network interface on the local network. Its first 24, 28 or 36 bits are an organisationally unique identifier that the IEEE Registration Authority assigns to manufacturers, so the prefix tells you who made the interface, or at least who registered the block.
The lookup uses our copy of the IEEE registry (MA-L, MA-M and MA-S blocks), longest match first: a small block assigned inside a larger one belongs to its own holder.
Two bits in the first byte change the meaning. If the locally administered bit is set, the address was chosen by software, not burnt in by a vendor: modern phones and laptops use such random addresses on Wi-Fi to avoid being tracked. If the multicast bit is set, it is a group address rather than a device.
Ofte stillede spørgsmål
Can a MAC address be seen over the internet?
No. MAC addresses stay on the local network segment; websites never see them. This lookup is for addresses you found in your router, a switch or a log.
Why does my phone show a different MAC on each network?
Privacy protection: iOS, Android and Windows use a random, locally administered address per Wi-Fi network by default.
Does the vendor tell me the device brand?
It tells you who registered the block, which is often the maker of the network chip, not the brand on the device.