MAC Address and OUI Lookup

This program displays the name of the company that manufactured your network card. You can also do a reverse lookup and find the MAC addresses registered by a company. You can also generate random MAC addresses.

What is a MAC address? What is OUI? What are MA-L, MA-M, MA-S?

A MAC address is a unique identifier for network interfaces. It is a 48-bit number (12 hexadecimal characters). They can either be written in either of these formats:

• MM:MM:MM:SS:SS:SS
• MM-MM-MM-SS-SS-SS

An OUI {Organizationally Unique Identifier} is a 24-bit number that uniquely identifies a vendor or manufacturer. They are purchased and assigned by the IEEE. The OUI is basically the first three octets of a MAC address. For example, these are examples of OUI:

• 00:00:0A -- this is owned by Omron
• 00-0D-4B -- this is owned by Roku, LLC

MA-L, or MAC Address Block Large is a block of MAC addresses where the maximum number of addresses is 2²⁴ or 16 million. MA-L was previously known as OUI.

MA-M, or MAC Address Block Medium, is a block of MAC addresses where the maximum number of addresses is 2²⁰ or 1 million.

MA-S, or MAC Address Block Small, is a block of MAC addresses where the maximum of addresses is 2¹² or 4096. MA-S was previously known as OUI-36. IAB is also known as Individual Address Blocks and the number of addresses is 2²⁴ or 16 million.

Read my article about MAC addresses

How to find the MAC address

How to find the MAC address in Windows

• Go to the DOS prompt
  • Click on Start button, select Run
  • Type cmd and press ENTER
• In the DOS prompt, type ipconfig /all and press ENTER
  You should see the MAC address in this format 00:00:00:00:00:00

How to find the MAC address in Unix or Linux

• Go to a terminal
• In the terminal, type ifconfig and press ENTER
  You should see the MAC address in this format 00:00:00:00:00:00 following HWaddr

How to find the MAC address in Mac OS

• Go to Utilities (Finder > Utilities OR command + shift + u) and start the Terminal app.
• Type this in the Terminal:

  networksetup -listallhardwareports
  

• You will see a list of all the network interfaces with their MAC addresses (Ethernet Address). An example output is this:

  networksetup -listallhardwareports
  
  Hardware Port: Bluetooth DUN
      Device: Bluetooth-Modem
  Ethernet Address: N/A
  
  Hardware Port: Ethernet
      Device: en0
  Ethernet Address: 10:dd:b1:xx:xx:xx
  
  Hardware Port: FireWire
      Device: fw0
  Ethernet Address: 10:dd:b1:ff:fe:xx:xx:xx
  
  Hardware Port: Wi-Fi
      Device: en1
  Ethernet Address: 4c:8d:79:xx:xx:xx
  
  Hardware Port: Bluetooth PAN
      Device: en3
  Ethernet Address: N/A
  
  VLAN Configurations
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