Question 1

What is a MAC address and what format does it use?

Accepted Answer

A MAC (Media Access Control) address is a unique 48-bit hardware identifier assigned to network interface cards. It is typically written as six groups of two hexadecimal digits, separated by colons (AA:BB:CC:DD:EE:FF), hyphens (AA-BB-CC-DD-EE-FF), or dots in three groups of four (AABB.CCDD.EEFF). The first three octets identify the manufacturer (OUI) and the last three are device-specific.

Question 2

What is the difference between unicast and multicast MAC addresses?

Accepted Answer

The least significant bit of the first octet determines the type. If it is 0 the address is unicast, meaning it identifies a single network device. If it is 1 the address is multicast, meaning the frame is intended for a group of devices. Most real hardware uses unicast addresses. Our generator lets you choose either type for testing purposes.

Question 3

What does locally administered vs globally unique mean?

Accepted Answer

The second least significant bit of the first octet indicates whether the address is globally unique (assigned by the manufacturer via IEEE OUI registration) or locally administered (set by software or a network administrator). Locally administered addresses are commonly used in virtual machines, containers, and privacy features like MAC randomization on mobile devices.

Fake MAC Address Generator