MAC Address Lookup
OUI Vendor Checker and Device Finder
Enter any MAC address, hardware address or OUI prefix to identify the device manufacturer from the IEEE registry. And when there is no manufacturer to find — because the address was generated in software, as every modern phone does by default — this tells you that plainly, instead of reporting it as “vendor not found” and leaving you to guess why.
Robert Harrison
OSINT and Network Utility Expert
Robert works on hardware forensics and Layer 2 diagnostics — the OUI registry, the bits inside an address, and working out what is actually sitting on a network.
The thing that makes most MAC address lookup tools frustrating is that they have one answer for two very different situations. Ask about a randomized phone address and you get “vendor not found”, which sounds like the search failed. Ask when the registry happens to be down and you get the same words, which sounds like a fact about your hardware. Neither is true.
So this one separates them. A locally administered address is identified from the U/L bit, which is arithmetic on the first byte and cannot be wrong. A registry outage says it is an outage. Multicast and broadcast are named rather than reported as missing. The whole IEEE registry — 52,085 prefixes — is held here rather than fetched, so nothing depends on an upstream being awake.
The other thing I wanted was an answer to the question people are actually asking. “Samsung Electronics Co.,Ltd” is correct and unhelpful when what you want to know is whether the unknown row in your router is a phone or a fridge. So the result says what the manufacturer builds, and says plainly when the prefix cannot narrow it further. Paste a whole arp -a table and it does the same for every line.
Last reviewed 28 August 2026 · Published 25 August 2026 · Nothing you enter is stored
View all articles by Robert HarrisonWhat Can a MAC Address Lookup Actually Tell You?
One thing: who made the network chip. That is worth knowing and it is a much smaller claim than most pages on this subject imply.
Every network interface carries a 48-bit identifier — the MAC address, also called the hardware or physical address. The first 24 bits are the OUI, an Organizationally Unique Identifier that the IEEE Registration Authority assigns to a company. The remaining 24 bits are a serial number that manufacturer gave to that individual card.
So a lookup reads the first half and reports the company. The IEEE publishes the full registry, and it runs to tens of thousands of assignments — Apple, Cisco, Samsung, Intel, Espressif, and a very long tail of manufacturers you will never have heard of.
What it cannot tell you is anything about a person. A MAC address contains no name, no account and no location. It identifies a chip, not an owner. If the reason you are here is that an unfamiliar device is on your Wi-Fi, the honest answer is that the manufacturer narrows down what it is — and the effective response is changing the password, not tracing the address.
One tool, a dozen names
This page answers to whatever you searched for. A MAC address checker, MAC address finder, MAC address identifier, MAC address resolver, MAC address decoder and MAC address search all describe the same operation: read the prefix, name the company. A MAC vendor finder is the same thing again, and so is any MAC lookup tool that returns a company. So are hardware address lookup and ethernet address lookup, the older terms for the same 48-bit value — Windows still labels it “Physical Address” in ipconfig.
One thing worth knowing before you paste: Bluetooth address lookup works here too. Bluetooth device addresses are drawn from the same IEEE space and are formatted identically, so the same prefix rules apply — an MA-L assignment covers a company's Ethernet, Wi-Fi and Bluetooth interfaces alike.
People also reach for WHOIS MAC by analogy with domains, and the comparison is worth unpicking because it explains a limitation. A domain WHOIS returns a registrant — a person or a company who registered that name. A MAC vendor check returns only the manufacturer who bought the prefix. There is no registrant behind an individual address, which is why no MAC vendor ID service can tell you who owns a device.
The three answers, and why they are different
Most tools give a vendor name or nothing. There are really five outcomes and the difference between them matters:
- A vendor name. The prefix is a factory assignment and the registry has it.
- Locally administered. The address was generated in software, so there is no manufacturer and never was. Determined from one bit, so this answer is exact.
- Multicast or broadcast. Not a device address at all — a group destination. Also exact.
- Genuine prefix, no record. Rare. A recent assignment, or a small MA-M or MA-S block where six digits are not enough.
- Registry unreachable. A problem here, not a finding about your address. Said out loud rather than dressed up as a result.
What Kind of Device Is This? Reading the Vendor Name
The MAC address manufacturer is not the device name, and the gap between the two is where most lookups leave you stranded. Knowing the brand is a start; MAC address identification only becomes useful when it tells you what the thing does. “Samsung Electronics Co.,Ltd” is a correct answer to a question you probably were not asking. You wanted to know whether the thing on your network is a phone, a television or a fridge, and Samsung makes all three behind the same prefix.
So the lookup above adds a second line under the MAC address vendor: what that manufacturer actually builds. It is worth being precise about how far that can honestly go. There is no public mapping from an OUI to a product model, and any tool implying otherwise is guessing. What the prefix genuinely narrows down falls into three bands.
Manufacturers that make one thing
These are the clean answers. A Raspberry Pi Foundation prefix is a Raspberry Pi, because the Foundation makes single-board computers and nothing else. Sonos is a speaker. Roku is a streaming player. Ring is a doorbell or a camera. ecobee is a thermostat. When the vendor has one product line, identifying the vendor identifies the device.
Chip makers, which rule things out
This band is more useful than it first looks. Intel, Realtek, Broadcom and MediaTek do not sell finished devices — they sell the network chip inside somebody else’s. An Intel prefix means a desktop or laptop running Windows or Linux, because Intel does not make phones. That single fact eliminates most of what an unknown device could be, even though it never tells you whether the machine is a Dell or a Lenovo.
Espressif belongs here too, and it is the one worth memorising. Their ESP32 and ESP8266 chips sit inside a large share of inexpensive smart plugs, bulbs, sensors and hobby projects. An Espressif prefix almost always means a small IoT device, though the same chip is in a shop-bought smart bulb and a homemade sensor alike.
Companies with many product lines
Apple, Samsung, Google, Amazon, LG and Microsoft each run everything through one shared pool. An Apple prefix could be an iPhone, iPad, Mac, Apple TV, Watch, HomePod or an AirPods case. The tool says so plainly rather than picking one and sounding confident. When the answer is ambiguous, knowing that it is ambiguous is more useful than a confident guess.
The one call the tool makes with certainty: virtual machines. VMware, VirtualBox, Hyper-V, QEMU/KVM and Parallels each generate adapter addresses from known blocks, so a MAC address lookup can tell you the “device” is not hardware at all. That is detected from the prefix rather than the company name, which matters — the registry lists 00:15:5D as plain “Microsoft”, with nothing to say it is a Hyper-V guest.
People search for ways to identify device by MAC address as though one number could name the thing outright, and it cannot. The honest sequence when you want to find device names on your own network is two-step: the lookup narrows the hardware to a category, and your router’s client list supplies the hostname. Neither works alone. Together they usually settle it in under a minute.
How Do You Identify an Unknown Device on Your Network?
Most people running a hardware address lookup are not doing inventory. They have opened the router admin page, found something they do not recognize, and want to know what it is before deciding whether to worry.
Get the address from the router, not the device
Two devices answering to the same address is a different problem, and our guide to resolving IP address conflicts covers that. To identify one unknown row, log in to the router — usually 192.168.0.1 or 192.168.1.1 — and open the connected clients or DHCP leases list. Each row has a hostname, a local IP and a MAC address. The hostname is often blank or meaningless, which is exactly why the address matters.
Read the result honestly
The manufacturer usually settles it quickly. An Amazon Technologies prefix on an unrecognized device is an Echo or a Fire TV. Espressif is almost always a smart plug, bulb or sensor, because their chips are in most cheap IoT hardware. Raspberry Pi Foundation is a Pi somebody set up and forgot.
But the commonest result now is no manufacturer at all, and that is the one worth understanding.
An “unknown” device is very often a household phone. Every modern phone randomizes its Wi-Fi address per network by default, so the address in your router bears no relation to anything printed on the device. Before assuming an intruder, count the devices you expect against the list — phones, laptops, tablets, TV, console, speakers, doorbell, plugs. The number is usually higher than people guess.
If the concern is genuinely that somebody outside the household is connected, the effective step is changing the Wi-Fi password, which disconnects everything and forces each device to re-authenticate. MAC filtering is not a substitute, because an attacker can copy an allowed address in seconds. If the device is reaching the internet from somewhere unexpected, an IP lookup names the network it routes through and a blacklist check shows whether that address has been reported.
Bulk MAC Address Lookup: Checking a Whole ARP Table at Once
Auditing a network one address at a time is not how anybody actually works. You have an arp -a dump, a DHCP lease list copied out of a router, a Wireshark export or a spreadsheet column — and you want the manufacturer beside every row. The bulk MAC lookup tab takes that whole mess and does exactly that.
Deliberately, it does not ask for a tidy list. Paste the raw output, with its IP addresses, interface headers, hostnames and timestamps still in it. Every MAC-shaped token gets pulled out and everything else is ignored. Colons, dashes, Cisco dotted notation and bare hex can all sit in the same paste, because separators are stripped before anything is compared.
What comes back
- The vendor for every address the registry knows — and a plain verdict where there is no vendor to find
- The likely device category, so a forty-row table reads as phones, printers and access points rather than company names
- Duplicates collapsed with a count, because an ARP table repeats the same address across interfaces
- Multicast and broadcast rows labelled as such rather than reported as failed lookups
- The whole table copyable as text or CSV, for pasting into a ticket or a spreadsheet
Two practical notes. IP addresses are never mistaken for MAC addresses, which sounds obvious until you paste an ARP table and a lesser tool returns nonsense for every other row. And the whole thing runs against the built-in registry rather than a remote API, so a hundred and fifty addresses cost nothing and finish instantly.
Getting the input: on Windows and macOS, arp -a lists every address your machine has spoken to recently. On Linux, ip neigh does the same. A router’s DHCP lease page is usually the better source for a home network, because it shows devices that have not sent traffic lately.
Reverse MAC Lookup: Finding Every Prefix a Vendor Uses
An OUI lookup normally runs one way: address in, company out. The reverse MAC lookup tab runs the other way: type a manufacturer and get the OUI prefixes registered to them. Useful when you are writing a filter rather than identifying one device — if you need to match every Cisco access point on a network, you need the prefix list, not a single answer.
It is also the quickest way to verify a MAC address prefix belongs to who you think it does — the kind of MAC address verification that comes up when a device claims to be one thing and the hardware says another. Searching Apple returns a long list, which is itself the point. Large manufacturers hold hundreds of blocks, so the absence of a familiar prefix means nothing.
What is actually in the database
The MAC address database behind this page is a snapshot of the IEEE registry, and it is worth stating its size honestly rather than implying it is infinite:
| Block type | Prefix length | Prefixes held | Typical holder |
|---|---|---|---|
| MA-L | 24 bits · 6 hex | 38,930 | The classic OUI. Any company with real volume. |
| MA-M | 28 bits · 7 hex | 6,262 | Mid-size manufacturers sharing a parent block. |
| MA-S | 36 bits · 9 hex | 6,893 | Small runs — industrial and specialist kit. |
That is 52,085 prefixes across roughly 29,500 companies, held locally so a lookup needs no network call. The three block sizes matter more than they look: a company holding an MA-S block sits inside another company’s MA-L range, so the search tries the longest prefix first. Checking only the first six digits would report the block owner instead of the actual manufacturer — a mistake plenty of MAC vendor lookup tools still make.
Anything registered after the snapshot still resolves, because a single lookup falls through to the live registry when the local copy has no record. Bulk results mark those honestly rather than inventing a name.
Common MAC Address Prefixes You Will Actually Meet
Most home and office networks are made of the same two dozen MAC address vendors. This MAC lookup table — or MAC lookup chart, whichever you searched for — covers the prefixes that turn up most often, with what each one usually means when it appears in a router’s client list. Every one is a real IEEE assignment — check any of them in the tool above.
| Prefix | Registered to | What it usually is |
|---|---|---|
| A4:83:E7 | Apple | iPhone, iPad, Mac — Apple shares one pool across all lines |
| 00:12:47 | Samsung Electronics | Galaxy phone, tablet, TV or appliance |
| B8:27:EB | Raspberry Pi Foundation | A Raspberry Pi, almost certainly |
| 00:1B:21 | Intel | A Windows or Linux PC — not a phone |
| 5C:CF:7F | Espressif | Smart plug, bulb or sensor built on an ESP chip |
| 00:00:0C | Cisco Systems | Switch, router, access point or IP phone |
| C0:25:E9 | TP-Link | Router, extender, or a Kasa/Tapo smart plug |
| FC:EC:DA | Ubiquiti | UniFi access point, switch or camera |
| 00:17:88 | Philips Lighting | A Hue bridge — the bulbs use Zigbee and never appear |
| 18:B4:30 | Nest Labs | Thermostat, smoke alarm, doorbell or camera |
| 00:14:22 | Dell | Desktop, laptop or server |
| 00:1B:A9 | Brother Industries | A printer, usually the one nobody remembers connecting |
| 00:50:56 | VMware | A virtual machine, not physical hardware |
| 08:00:27 | Oracle VirtualBox | A VirtualBox guest |
| 00:15:5D | Microsoft | A Hyper-V virtual machine, despite the plain name |
To check MAC address vendor details for a prefix that is not listed here, use the tool at the top — a prefix missing from this table means nothing, since it holds fifteen of 52,085. Use the reverse tab to pull the full list for any manufacturer, or run the address itself through the MAC address checker above.
Inside a 48-Bit Address: OUI, Serial and Two Important Bits
A MAC address is twelve hexadecimal digits — six bytes, 48 bits. It looks arbitrary and is not. Of all the MAC address identifiers a network hands around, this is the only one burned in at the factory.
The OUI, and the two bits hiding in it
The first three bytes identify the manufacturer, who bought that prefix from the IEEE. Large companies own hundreds of them. But two bits of the very first byte are not part of the company identity at all — they are flags, and they carry most of the interesting information.
The I/G bit is the least significant bit of the first byte. Set means the address is a group destination — multicast — rather than one card. The U/L bit is the next one along. Set means the address is locally administered: made up in software rather than assigned in a factory.
# Reading the first byte of 00:1B:44:11:3A:B7
00 hex = 0000 0000 binary
││
│└─ I/G bit = 0 → unicast, one device
└── U/L bit = 0 → universally administered, real vendor
# The shortcut, stated correctly:
# U/L is set whenever the SECOND hex digit is 2 3 6 7 A B E F
# of those, 3 7 B F also have I/G set, so they are multicast
# which leaves 2 6 A E as the ones on a normal device address
DA:A1:19:... → second digit A → randomized or spoofed
A4:83:E7:... → second digit 4 → genuine Apple assignment
That shortcut is the single most useful thing on this page, and it is worth stating precisely because almost everywhere else states it wrong.
The version you will read elsewhere is incomplete. Nearly every guide says the U/L bit is set when the second digit is 2, 6, A or E. Eight values set it, not four — 2, 3, 6, 7, A, B, E and F. The four that get left out are the ones where the I/G bit is set as well, which makes them multicast rather than device addresses. So the short version is a fine rule of thumb for a normal unicast address and a wrong statement about the bit itself. Now you know which it is.
The serial half
The last three bytes are assigned by the manufacturer to each card they build, which is what keeps addresses globally unique. Two identical laptops on the same desk differ here, and that is how the switch tells them apart. Nothing in this half is searchable — there is no public registry of individual serials, and there is no way to go from one to a device, a model or an owner.
Randomization and Spoofing: Why Lookups Fail on Purpose
Because a factory MAC address never changes, it was a perfect tracking identifier — a shop with Wi-Fi could log the same address on Tuesday and Friday and know the same person walked in twice. Operating systems fixed that by lying.
Who randomizes, and when
- iOS 14 and later uses a different private address for every Wi-Fi network, on by default.
- Android 10 and later randomizes for all Wi-Fi connections by default.
- Windows 10 and 11 offer random hardware addresses as a per-network setting, off by default on most builds.
- Recent macOS uses a private address per network, on by default.
Which means a very large share of the addresses in any modern router's client list have no vendor at all, and never did. This is not a failure of the lookup. It is the feature working.
The same bit that makes those addresses unreadable is the one you set on purpose when you need an address of your own — for a virtual machine, a test rig or a lab. The MAC address generator builds them the right way round, locally administered and unicast, instead of rolling forty-eight random bits and hoping.
To see a device's real address, turn off the private-address setting for that specific network in the device's own Wi-Fi settings, then reconnect. On iOS that is the network's info panel; on Android it is the network's advanced settings. The randomized address is per-network, so switching it off for your home Wi-Fi does not affect anything else.
Spoofing, and what an OUI mismatch actually tells you
Deliberate MAC spoofing is the same mechanism used on purpose — changing the reported address to get past a filter or to impersonate a permitted device. Because the U/L bit gives away a locally administered address, careful spoofing copies a real vendor prefix instead, which defeats the bit check entirely. That is the limit of what any bit-level test can do: it catches the lazy version and nothing else.
What still helps is context. A device reporting itself as a laptop with an OUI belonging to VMware is a virtual machine. A prefix that has no business being on the network at all is worth asking about. Neither is proof, and both are worth a second look.
MAC filtering is not a security control. It is worth saying plainly, because it is still recommended in a lot of router documentation. Any allowed address can be read off the air by anyone nearby and copied in one command, and the filter then permits the attacker exactly as it permits you. It stops casual neighbours and nothing else. WPA3, or WPA2 with a long passphrase, is the control that matters.
Whose MAC Address Is This? What a Lookup Cannot Tell You
No lookup on earth will tell you who owns a MAC address. Not this one, not a paid one, not a law-enforcement one. The address contains a manufacturer code and a serial number. There is no name field, no account, no registry of owners, and nothing to cross-reference against. This is worth saying directly, because a great many pages imply otherwise and a few sell subscriptions on the strength of it.
Why there is nothing to find
The IEEE registers prefixes to companies, not to buyers. When Apple sells a phone, nothing is recorded anywhere linking that serial to a person. The manufacturer may know which batch shipped to which distributor. Nobody knows who ended up holding it.
Nor can a MAC address tracker follow one across the internet, for a more fundamental reason: the address never leaves the local network. Your router strips it and substitutes its own before anything is forwarded. A website sees your public IP and never the hardware address behind it. Anything advertising itself as a MAC locator is describing something it cannot do.
What actually works instead
- An unfamiliar device on your Wi-Fi: change the password. Everything disconnects and has to re-authenticate, which removes anything you did not authorise. MAC filtering is not a substitute — an allowed address can be copied in seconds.
- Working out which of your own devices it is: unplug things one at a time and watch the router’s client list. Crude, and faster than anything else.
- Something reaching your network from outside: that is an IP question, not a MAC one. Our IP geolocation lookup names the network an address routes through.
- A device you suspect is misbehaving: the vendor and category from the lookup, plus what ports it has open, tells you far more than an owner name would. The port scanner covers that half.
The distinction between a hardware address and a routable one is the whole reason this is true, and it is explained properly in our guide to MAC addresses versus IP addresses.
Formats, EUI-64, and Finding Your Own Address
The same address gets written four different ways depending on who is printing it. All four are accepted above — separators are stripped before anything else happens.
| Format | Example | Where you see it |
|---|---|---|
| Colon-separated | 00:1B:44:11:3A:B7 | Linux, macOS, most documentation |
| Dash-separated | 00-1B-44-11-3A-B7 | Windows ipconfig /all |
| Dot-separated | 001B.4411.3AB7 | Cisco IOS |
| Raw hex | 001B44113AB7 | Logs, databases, APIs |
Finding your own
# Windows
ipconfig /all # read "Physical Address"
getmac /v # shorter output
# Linux
ip link show
# macOS
ifconfig en0 | grep ether
On macOS through the interface: System Settings, Network, Wi-Fi, Details, Hardware. On iPhone: Settings, General, About, Wi-Fi Address. On Android: Settings, About Phone, Status. On both phones the value shown is usually the randomized one, not the factory address.
EUI-64, and where IPv6 comes in
IPv6 can build an interface identifier straight from a MAC address using modified EUI-64. It splits the 48-bit address in half, inserts FF:FE between the two halves and flips the U/L bit. The result is 64 bits that still trace back to the original OUI, which is precisely why privacy extensions exist and why most systems no longer do this by default.
# How EUI-64 is derived
MAC: 00:1B:44:11:3A:B7
Split: 00:1B:44 | 11:3A:B7
Insert FF:FE: 00:1B:44:FF:FE:11:3A:B7
Flip U/L bit: 02:1B:44:FF:FE:11:3A:B7
IPv6 suffix: ::021B:44FF:FE11:3AB7
This tool accepts a 16-digit EUI-64 as well as a 12-digit MAC and a 6-digit OUI. To expand or compress the IPv6 address itself, the IPv6 expansion tool handles that, and the cloud IP check tells you whether an address belongs to a datacentre rather than a home connection.
Frequently asked questions about MAC address lookup
How do I look up multiple MAC addresses at once?
Use the bulk tab and paste the text you already have — arp -a output, a DHCP lease list, a CSV column or a log file. Every MAC-shaped token is extracted and everything else is ignored, so there is no need to tidy the input first. Colon, dash, Cisco dotted and bare hex formats can all appear in the same paste. Duplicates are collapsed with a count, and the whole table copies out as text or CSV.
Can I find all the MAC address prefixes a manufacturer uses?
Yes — that is what the reverse tab does. Enter a company name and it returns the OUI prefixes registered to them from a local snapshot of 52,085 assignments. Large manufacturers hold hundreds of blocks, so a familiar prefix being absent from a short list means nothing. This is the direction you want when writing a firewall rule or an inventory filter rather than identifying one device.
Can a MAC address lookup tell me what device it is?
Partly, and the limit is worth knowing. The prefix names the manufacturer, and this tool adds what that manufacturer actually builds. Single-product companies give a clean answer — a Raspberry Pi prefix is a Raspberry Pi. Chip makers narrow it usefully: an Intel prefix means a PC or laptop, not a phone. Companies like Apple and Samsung share one pool across every product line, so the honest answer there is a category rather than a model.
Who owns this MAC address?
Nobody can tell you, and no service can. The address holds a manufacturer code and a serial number — there is no name, no account and no owner registry to check. The IEEE registers prefixes to companies, not to buyers, so nothing anywhere links a specific address to a person. If an unfamiliar device is on your Wi-Fi, changing the password is the effective response.
How many MAC address prefixes are in the database?
52,085 — 38,930 MA-L blocks, 6,262 MA-M and 6,893 MA-S, covering roughly 29,500 companies. It is held locally, so lookups need no network call and bulk checks are instant. The search tries the longest prefix first, because a company holding a small MA-S block sits inside another company’s larger range and checking only the first six digits would name the wrong firm.
What is a MAC address lookup and how does it work?
It identifies the manufacturer of a network device from the first six hex digits of its MAC address — the OUI, or Organizationally Unique Identifier. The IEEE Registration Authority assigns those prefixes to companies, so A4:83:E7 means Apple and B8:27:EB means a Raspberry Pi. The last six digits are the serial the manufacturer gave that individual card and identify nobody.
Why does my MAC lookup say the vendor was not found?
Usually because there is no vendor to find. If the second hex digit is 2, 6, A or E the address was generated in software rather than assigned in a factory — every modern phone does this by default. This tool says so explicitly instead of reporting it as a failed search, because “not found” and “there was never anything to find” are very different answers.
Is it true that 2, 6, A and E mean a randomized MAC address?
For a normal device address, yes — but the rule as usually written is incomplete. The U/L bit is set by eight second-digit values, not four: 2, 3, 6, 7, A, B, E and F. The four left out of the popular version are the ones where the I/G bit is set too, which makes them multicast group addresses rather than device addresses. So 2, 6, A and E is a sound rule of thumb for a unicast address and a wrong statement about the bit itself.
Can I find a person, a location or a device owner from a MAC address?
No. A MAC address carries the manufacturer and a serial number and nothing else — no name, no account, no location. It is a hardware identifier, not personal data. If you are trying to work out who is on your network, counting your own devices and changing the Wi-Fi password gets you further than tracing an address ever will.
Can a website see my MAC address?
No. Your router strips it before packets leave the local network, so anything past your own gateway never sees it. Your router sees it, your ISP sees your router’s, a public Wi-Fi access point sees it when you associate, and apps installed on the device with the right permissions can read it. A web page cannot. The distinction between a hardware address and a routable one is covered in our MAC address versus IP address guide.
What is the difference between an OUI and a MAC address?
The OUI is the first 24 bits of the 48-bit address. Those bits identify the manufacturer; the remaining 24 are assigned by that manufacturer to the individual network card. So every MAC address contains an OUI, and an OUI on its own is enough to identify the vendor but not the device.
How do I find my own MAC address?
On Windows, run ipconfig /all and read Physical Address. On macOS, System Settings, Network, Wi-Fi, Details, Hardware. On iPhone, Settings, General, About, Wi-Fi Address. On Android, Settings, About Phone, Status. On phones the value shown is often the randomized one rather than the factory address.
Is MAC address spoofing illegal?
Changing your own device’s address is not illegal in most countries, and it is exactly what your phone does automatically for privacy. Using a spoofed address to get past an access control you were not granted is a different matter and is illegal in most places under computer-misuse law. The technique is neutral; the use is not.
Can two devices have the same MAC address?
Factory-assigned addresses are meant to be globally unique and collisions are rare. Randomized and locally administered addresses can collide, and occasionally a manufacturer ships a batch with duplicates. Two devices with the same address on one segment will both suffer, because the switch cannot tell them apart and traffic ends up at the wrong one.
What is an EUI-64 identifier?
A 64-bit version of the same idea, used by IPv6 to build an interface identifier from a 48-bit MAC address. The process splits the MAC in half, inserts FF:FE in the middle and flips the U/L bit. This tool accepts 16-digit EUI-64 input as well as 12-digit MAC and 6-digit OUI.
What happens if the vendor database is down?
The page says so rather than telling you the address is unregistered. The commonest few dozen prefixes are held locally and answer without any network call, and the bit-level analysis — unicast or multicast, universal or local — is arithmetic on the first byte and never needed the network at all. Only the manufacturer name for an uncommon prefix depends on the upstream registry.
Related network tools
Once you know the hardware, these tell you about the network it is on.
Browse the full set on the TrustMyIP tools directory.
Found a device you cannot place?
The manufacturer usually settles it. And if the answer comes back as randomized, that is an answer too — it means you are almost certainly looking at somebody's phone.
Last updated 28 August 2026 · OUI data from the IEEE registry · Nothing you enter is stored