MAC Address

MAC-48 or EUI-48

  • MAC : Media Access Control

  • EUI: Extended Unique Identifier Example: 00-40-05-60-7D-49

  • No two NICs share MAC addresses. Always have to be unique.

  • Uses hexadecimal notation

  • 48 bits total with 12 4 bit chars

    • 48-bit binary address or 6-byte binary address

  • IEEE issues MAC address to manufacturer, referred to as OUI

    • OUI: Organizationally Unique Identifier

  • NICs send a Layer 2 broadcast of FF-FF-FF-FF-FF-FF to request NICs MAC addresses. Every NIC on the network will process this.

  • When the MAC address isn’t known a NIC can use the IP address (Layer 3) to request the MAC address of the target NIC.

Run these in terminal to see MAC addresses: Linux: ip a Windows: ipconfig /all MacOS: ifconfig

  • TODO: file bug report and/or fix links embeded in bolded text in VimWiki