Using the Enterramon MAC Address Lookup
What is a MAC address lookup
Every network device, a router, a laptop’s wifi card, a smart TV, a phone, ships with a MAC address burned into its hardware. It’s a 12-character identifier, and the first six characters of it aren’t random, they’re assigned by the IEEE to a specific manufacturer. That block is called the OUI, the Organizationally Unique Identifier, and it’s the same for every device that vendor has ever made.
A MAC address lookup takes that prefix and matches it against the IEEE’s public registry, so instead of a meaningless string of hex characters, you get an actual answer, this device was made by this manufacturer.
Our MAC Lookup tool does exactly that, matched against our own copy of the IEEE OUI database.
Using the Enterramon MAC Lookup
Head to enterramon.com/mac-address-lookup and enter a MAC address, or just the prefix if that’s all you have.
You can enter as little as three octets, AA:BB:CC, or the full six-octet address, AA:BB:CC:DD:EE:FF. Either format works, since the manufacturer is determined entirely by that first block, the rest of the address is unique to the individual device and won’t change which vendor comes back.
Hit Look Up and we check that prefix against the IEEE registry.
Understanding the MAC lookup results
Registered Vendor
The manufacturer assigned that OUI block, straight from the IEEE registry. This is the answer you’re actually here for, everything else on the page is supporting detail.
Registry
IEEE actually maintains a few different sizes of assignment block, not just one. MA-L (MAC Address Block Large) is the traditional 24-bit block, covering a large range of addresses for that vendor. MA-M and MA-S are medium and small blocks, used by vendors who only needed a smaller allocation. The registry type tells you which size block the match came from, which is also why our tool checks prefixes at more than one length, a 24-bit match, then narrower, until it finds a hit.
Matched Prefix
The exact prefix that produced the result, along with its bit length. Worth checking this against what you actually entered, particularly if you pasted a full address and expected a different vendor back, this confirms exactly which portion of the address the match was based on.
Import Batch and Last Updated
These tell you when our copy of the IEEE database was last refreshed. The registry itself updates fairly often as new vendors register, so if you’re looking up a recently released device and getting no match, the record simply may not have existed yet at the last import.
How MAC lookup can help you
The most common use is spotting something on a network that shouldn’t be there. If you’re looking at a DHCP lease list or a switch’s MAC table and see an address you don’t recognise, the vendor lookup is often enough to tell you what kind of device it actually is, a phone, a smart TV, a laptop, without needing physical access to it.
It’s also useful for basic inventory work. Confirming that a batch of devices are what they claim to be, cross-checking a purchase order against what’s actually connecting to the network, or catching a MAC-spoofed device masquerading as something it isn’t, since a spoofed address will often use a prefix from a completely different, sometimes suspiciously generic, vendor.
And it comes in handy for plain troubleshooting too. Resolving an IP conflict, confirming which physical device is holding a particular lease, or just working out what’s actually plugged into a port when the label’s long gone.
What MAC lookup is not
A MAC lookup identifies the manufacturer of a device’s network interface. It does not identify the specific device, its owner, its location, or anything else about it. Two completely unrelated laptops from the same manufacturer will show the identical vendor result, since the OUI only narrows things down to “who made this,” not “which one is this.”
It’s also not going to work for every address you throw at it, and that’s expected, not a bug. A few reasons a lookup can come back empty.
The address could be a locally administered address rather than a manufacturer-assigned one. If the second hex character of the address is 2, 3, 6, 7, A, B, E, or F, that’s a deliberate signal in the address itself that it was set locally rather than assigned by the IEEE, and it will never appear in the registry.
It could also be a randomized MAC address. iOS, Android, Windows, and macOS all now generate temporary randomized addresses by default for privacy when a device joins a wifi network, specifically so it can’t be tracked by its real hardware address across networks. That’s a deliberate privacy feature working as intended, not a lookup failure.
It could be a virtual MAC address generated by a hypervisor, a spoofed address changed by software, or a special-purpose reserved range like multicast or broadcast addresses, none of which map to a real hardware manufacturer in the first place.
So an empty result doesn’t necessarily mean something’s wrong with the address. Sometimes it means the address was never meant to be traceable to begin with.
