MAC OUI Vendor Lookup

Look up the manufacturer of a MAC address from the IEEE OUI database, or reverse-search a company name to list all its OUI blocks — fully offline

Two modes against a bundled offline copy of the IEEE OUI database (39,227 OUI blocks): (1) MAC address → vendor — parses any common format, decodes the OUI, shows the registered organization/address and the address type (UAA / locally administered / multicast) from the U/L and I/G bits, plus format conversions; (2) Company name → OUI list — tokenized reverse search returning all OUI blocks registered to matching organizations, grouped by company.

Example Results

2 examples

Look up the vendor of a single MAC address

Normalize the input, decode the OUI, and show the registered organization from the IEEE database.

MAC OUI vendor lookup result with address type and format conversions.
View input parameters
{ "mode": "forward", "input": "00:1B:21:3C:4D:5E", "maxResults": 50 }

Reverse-search all OUI blocks owned by a company

Enter a company name and list every OUI block registered to matching organizations.

Reverse lookup grouped by organization with all matching OUI blocks.
View input parameters
{ "mode": "reverse", "input": "Apple", "maxResults": 50 }

Key Facts

Category
Developer & Web
Input Types
select, text, number
Output Type
html
Sample Coverage
3
API Ready
Yes

Overview

The MAC OUI Vendor Lookup tool allows you to instantly identify the manufacturer of any network device using its MAC address, or reverse-search a company name to retrieve all its registered IEEE OUI blocks. Operating entirely offline against a bundled database of over 39,000 OUI blocks, it decodes MAC address formats, identifies address types such as UAA, locally administered, or multicast, and provides clean format conversions.

When to Use

  • •When analyzing network traffic logs or ARP tables and you need to identify the physical manufacturers of connected devices.
  • •When auditing network security and verifying whether MAC addresses belong to legitimate hardware vendors or are locally administered/randomized.
  • •When researching hardware vendor allocations to find all OUI blocks registered to a specific company like Apple, Cisco, or Intel.

How It Works

  • •Select your lookup mode: choose 'MAC address → vendor' to identify a manufacturer, or 'Company name → OUI list' to find registered blocks.
  • •Enter your input, which can be a MAC address in any standard format (colon, hyphen, Cisco dot notation, or raw hex) or a company name.
  • •The tool parses the input offline against the IEEE OUI database, decodes the U/L and I/G bits to determine the address type, and outputs the matching vendor details or OUI list.

Use Cases

Identifying unknown devices on a local network by looking up their MAC addresses from an ARP table or DHCP lease list.
Generating a comprehensive list of OUI prefixes owned by a specific network hardware manufacturer for firewall or IDS configuration.
Decoding MAC address bits to verify if a device is using a randomized, locally administered, or multicast address.

Examples

1. Identify the Manufacturer of a Network Device

Network Administrator
Background
A network administrator notices an unfamiliar MAC address (00:1B:21:3C:4D:5E) in the router's DHCP client list and needs to verify the hardware vendor.
Problem
Identifying the manufacturer and address type of a specific MAC address.
How to Use
Select the 'MAC address → vendor' mode, enter '00:1B:21:3C:4D:5E' into the input field, and run the lookup.
Example Config
{
  "mode": "forward",
  "input": "00:1B:21:3C:4D:5E",
  "maxResults": 50
}
Outcome
The tool identifies the OUI as belonging to Intel Corporation, displays their registered address, and confirms it is a globally unique (UAA) unicast address.

2. Find All OUI Blocks Registered to Apple

Security Analyst
Background
A security analyst is configuring a network monitoring tool to automatically flag or categorize Apple devices based on their MAC address prefixes.
Problem
Retrieving a complete list of OUI blocks registered to Apple.
How to Use
Select the 'Company name → OUI list' mode, enter 'Apple' in the input field, set the maximum results to 100, and execute the search.
Example Config
{
  "mode": "reverse",
  "input": "Apple",
  "maxResults": 100
}
Outcome
The tool returns a grouped list of all OUI blocks registered to Apple, allowing the analyst to copy the prefixes for their monitoring rules.

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FAQ

What formats of MAC addresses does the tool support?

The tool supports all common MAC address formats, including colon-separated (00:1A:2B:3C:4D:5E), hyphen-separated (00-1A-2B-3C-4D-5E), Cisco dot notation (001a.2b3c.4d5e), and raw hexadecimal strings.

What is the difference between UAA and locally administered MAC addresses?

A Universally Administered Address (UAA) is globally unique and assigned by the IEEE to the manufacturer. A locally administered address is generated by software (like VMs or mobile MAC randomization) and will not appear in the IEEE OUI database.

Does this tool require an active internet connection?

No, the tool runs entirely offline in your browser using a bundled copy of the IEEE OUI database containing over 39,000 registered blocks.

Why does a valid MAC address show as 'not found' or unknown vendor?

This usually happens if the MAC address is locally administered (randomized), or if it belongs to a newer small-block allocation (MA-M, MA-S, or IAB) that falls outside the classic 24-bit OUI prefix matching.

How many results can I retrieve when reverse-searching by company name?

You can configure the tool to return up to 500 matching OUI blocks per search, grouped by the registered organization name.

API Documentation

Request Endpoint

POST /en/api/tools/mac-oui-vendor-lookup

Request Parameters

Parameter Name Type Required Description
mode select No -
input text Yes -
maxResults number No -

Response Format

{
  "result": "
Processed HTML content
",
  "error": "Error message (optional)",
  "message": "Notification message (optional)",
  "metadata": {
    "key": "value"
  }
}
HTML: HTML

AI MCP Documentation

Add this tool to your MCP server configuration: 

{
  "mcpServers": {
    "elysiatools-mac-oui-vendor-lookup": {
      "name": "mac-oui-vendor-lookup",
      "description": "Look up the manufacturer of a MAC address from the IEEE OUI database, or reverse-search a company name to list all its OUI blocks — fully offline",
      "baseUrl": "https://elysiatools.com/mcp/sse?toolId=mac-oui-vendor-lookup",
      "command": "",
      "args": [],
      "env": {},
      "isActive": true,
      "type": "sse"
    }
  }
}

You can chain multiple tools, e.g.: `https://elysiatools.com/mcp/sse?toolId=png-to-webp,jpg-to-webp,gif-to-webp`, max 20 tools.

If you encounter any issues, please contact us at [email protected]