What is a MAC address?

A MAC (Media Access Control) address is a 48-bit hardware identifier assigned to a network interface. It is represented as six groups of two hex digits and is used at the data link layer to uniquely identify devices on a local network.

What is the difference between UAA and LAA?

UAA (Universally Administered Address) is burned into hardware by the manufacturer and is globally unique. LAA (Locally Administered Address) is set by software and only needs to be unique within the local network. The second-least-significant bit of the first octet (bit 1) distinguishes them: 0 = UAA, 1 = LAA.

What is the difference between unicast and multicast?

Unicast addresses identify a single network interface. Multicast addresses target a group of interfaces. The least-significant bit of the first octet determines this: 0 = unicast, 1 = multicast. Broadcast (FF:FF:FF:FF:FF:FF) is a special multicast case.

Can I use these MAC addresses on a real device?

Generated addresses are suitable for virtual interfaces (VMs, containers, test hardware). For locally administered addresses, ensure uniqueness within your network segment. Do not spoof MAC addresses on public networks without authorization.

What is an OUI prefix?

The first three octets of a MAC address form the Organizationally Unique Identifier (OUI), assigned to vendors by the IEEE. Pinning the OUI lets you simulate devices from a specific manufacturer during testing.

What is Cisco dot notation?

Cisco IOS displays MAC addresses as three groups of four hex digits separated by dots, e.g. aabb.ccdd.eeff. It carries the same information as the colon or dash formats, just grouped differently.

MAC Address Generator

Name: MAC Address Generator
Availability: InStock
Author: Nham Vu

Generate one or many random MAC addresses with full control over format, unicast/multicast bit, and locally/globally administered bit.

Options

Number of addresses

Between 1 and 100

Format

AA:BB:CC:DD:EE:FF AA-BB-CC-DD-EE-FF AABB.CCDD.EEFF

Case

Uppercase Lowercase

Address type

Unicast Multicast

Controls bit 0 of the first octet

Administration

Locally (LAA) Globally (UAA)

Controls bit 1 of the first octet

OUI prefix (optional)

Pin the first 3 octets. Leave blank for fully random.

Results

Configure options and click Generate

First-octet bit breakdown

Bit 7 (MSB)	Bit 1	Bit 0 (LSB)	Meaning
varies	0	0	Unicast, Globally administered (UAA)
varies	1	0	Unicast, Locally administered (LAA)
varies	0	1	Multicast, Globally administered
varies	1	1	Multicast, Locally administered

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Summary

Generate one or many random MAC addresses with full control over format, unicast/multicast bit, and locally/globally administered bit.

How it works

Select how many MAC addresses you want to generate (1 to 100).
Choose the output format: colon, dash, or Cisco dot notation.
Set the address type: unicast (default) or multicast.
Set the administration scope: locally administered (LAA) or globally administered (UAA).
Optionally pin the first three octets (OUI prefix) to lock the vendor portion.
Click Generate, then copy individual addresses or the entire list.

Use cases

Populate test environments and network simulators with realistic MAC addresses.
Create virtual machine network interfaces for lab setups.
Generate locally administered addresses for private network testing.
Produce bulk MAC address lists for network inventory tooling.
Test network access control (NAC) policies in development environments.
Verify MAC address parsing and validation code in your application.
Simulate device discovery in IoT prototype firmware.
Generate multicast addresses for multicast group testing.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu