MAC Address & OUI Lookup

Free MAC address & OUI lookup. Identify device manufacturers, hardware vendors, and randomized MAC addresses instantly. Fast client-side database search.

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In-Depth Technical Guide

MAC Address Architecture & OUI Vendor Lookup: EUI-48, Bit Masks & Packet Analysis

Complete technical guide to MAC address architecture: IEEE OUI assignments, EUI-48 vs EUI-64, multicast/local bit masks, randomized MAC addresses, and network troubleshooting.

Read Full Guide (12 min read)

Technical Overview: How MAC Address & OUI Lookup Works

The MAC Address & OUI Lookup searches the IEEE Organizationally Unique Identifier (OUI) lookup database to identify device manufacturers from MAC addresses, analyzes bit-level flags (I/G, U/L), detects randomized private MACs, converts across 6 notations (including EUI-64), and supports reverse vendor search.

Performs local MAC OUI lookup against an offline-bundled IEEE OUI lookup database covering major manufacturers. Parses 48-bit MAC addresses across IEEE colon, Windows hyphen, Cisco dot, space, raw hex, and IPv6 EUI-64 SLAAC formats. Inspects the least-significant bits of the first octet to identify Unicast vs Multicast (I/G bit) and Universally vs Locally Administered (U/L bit).

Practical Examples & Usage

MAC OUI Lookup: IEEE Vendor Search via OUI Lookup Database

Input:MAC: B8:27:EB:01:02:03

Output:OUI: B8-27-EB | Vendor: Raspberry Pi Foundation | Address Type: Unicast, Universally Administered (UAA)

Uses the IEEE OUI lookup database to immediately identify the hardware manufacturer as Raspberry Pi Foundation.

Looking up Apple Hardware MAC Address

Input:MAC: 3C:06:30:11:22:33

Output:

OUI: 3C-06-30 | Vendor: Apple, Inc. | Address Type: Unicast, Universally Administered (UAA) | Formats: 3c:06:30:11:22:33 / 3c06.3011.2233

Matches the first 3 octets (3C:06:30) to Apple Inc. in the official IEEE OUI database and confirms global hardware assignment.

Detecting Randomized Private Wi-Fi MAC Address

Input:MAC: DA:A1:19:44:55:66

Output:

OUI: DA-A1-19 | Vendor: Unknown (Locally Administered / Randomized) | Bit Analysis: U/L bit = 1 (Local), I/G bit = 0 (Unicast)

Identifies locally administered randomized addresses commonly generated by iOS, Android, and Windows for Wi-Fi privacy.

Real-World Applications & Use Cases

Executing a MAC OUI lookup to match hardware network cards and IoT devices against the IEEE vendor registry.
Searching the OUI lookup database by vendor name to discover assigned MAC address blocks.
Identifying unknown devices, IoT hardware, and rogue endpoints connected to local Wi-Fi and corporate networks.
Detecting modern smartphone randomized private Wi-Fi MAC addresses during network access audits.
Troubleshooting network switch port mappings and DHCP client leases during IT infrastructure audits.
Calculating IPv6 Stateless Address Autoconfiguration (SLAAC) EUI-64 modified interface identifiers from MAC addresses.

How to use MAC Address & OUI Lookup

Enter any MAC address or 24-bit OUI prefix (e.g. 00:1A:2B:3C:4D:5E, 00-1A-2B, or raw hex).
Identify the physical hardware manufacturer (Apple, Cisco, Intel, Samsung, Raspberry Pi, etc.).
View normalized representations: Colon (IEEE), Hyphen (Windows), Cisco Dot, and IPv6 EUI-64.
Check bit-level analysis: Unicast vs Multicast (I/G bit) and UAA vs LAA (Locally Administered).
Switch to "Search OUIs by Vendor" to explore registered manufacturer prefixes directly.

Edge Cases & Limitations

•Modern smartphones (iOS Private Wi-Fi, Android MAC Randomization, Windows Random Hardware Addresses) use Locally Administered Addresses (LAA) that do not map to manufacturer OUIs.
•Virtual machines (VMware, VirtualBox, Hyper-V) use specific virtual OUI blocks rather than physical hardware vendors.
•IEEE OUI-36 (MA-S) and OUI-28 (MA-M) smaller block assignments may resolve to the parent block holder in basic 24-bit lookups.

Recommended Best Practices

•Check whether the "Locally Administered" bit is set if a device MAC does not resolve to an expected hardware vendor.
•Standardize on colon notation (XX:XX:XX:XX:XX:XX) for network documentation, firewall rules, and router configuration.
•Use 802.1X enterprise network security and certificate authentication rather than static MAC filtering alone.

Data Handling Profile

Client-side processing

Processing Runtime: All text transformations, mathematical calculations, code formatting, and asset conversions execute locally inside your web browser sandbox.
Memory & Storage: Processed text and parameters are handled in browser memory. Optional configuration preferences (like dark/light theme) are stored in your browser local storage for convenience.
Network Transmission: Tool inputs and calculation results are processed in browser memory and are not uploaded to Outlivo application servers.

Frequently Asked Questions

How do I perform a MAC OUI lookup to identify a device vendor?

Enter the 6-character OUI prefix or full 12-character MAC address into the search field. The lookup tool matches the prefix against the official IEEE OUI database to display the registered vendor name, country, and interface type.

What is an OUI in a MAC address?

OUI stands for Organizationally Unique Identifier. The first 3 bytes (24 bits) of a MAC address are assigned by the IEEE Standards Association to specific hardware manufacturers like Apple, Cisco, Intel, or Dell.

Why does my smartphone MAC address show as "Locally Administered"?

Modern mobile devices (iOS Private Wi-Fi, Android MAC Randomization, Windows Random Hardware Addresses) automatically generate randomized MAC addresses with the Locally Administered bit (bit 1) enabled to prevent cross-network Wi-Fi tracking.

What is the difference between EUI-48 and EUI-64?

EUI-48 is standard 48-bit MAC addressing. EUI-64 expands it to a 64-bit interface identifier by inverting the U/L bit and inserting 0xFFFE into the middle, utilized in IPv6 Stateless Address Autoconfiguration (SLAAC).

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