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MAC Address Generator
The MAC address generator creates random MAC (Media Access Control) addresses for use in network testing, virtual machine configuration, and simulation environments. You can generate universally administered addresses with a real OUI prefix, locally administered addresses (LAA), or multicast addresses. Bulk generation is supported for populating test environments.
What is a MAC Address?
A MAC address is a 48-bit hardware identifier assigned to a network interface controller (NIC). It is expressed as six pairs of hexadecimal digits separated by colons or hyphens (e.g., 00:1A:2B:3C:4D:5E). The first three octets form the Organizationally Unique Identifier (OUI), assigned by IEEE to a manufacturer. The last three octets are the device-specific identifier chosen by the manufacturer. Bit 1 of the first byte indicates whether the address is universally or locally administered; bit 0 indicates unicast vs multicast.
How does it work?
Select whether you want a universally administered address (with a real or random OUI), a locally administered address (bit 1 of byte 1 set to 1), or a multicast address (bit 0 of byte 1 set to 1). For universally administered addresses you can optionally specify an OUI prefix. The remaining bytes are generated using cryptographically secure random numbers. The output is displayed in colon, hyphen, and no-separator formats.
Typical Use Cases
- Generating MAC addresses for virtual machines in a lab environment
- Creating test data for network device inventory systems
- Simulating multiple client devices in network load tests
- Configuring a locally administered MAC for a virtual network interface
Step-by-step Guide
- Step 1: Select the address type (universally administered, locally administered, or multicast).
- Step 2: Optionally enter an OUI prefix for vendor-specific addresses.
- Step 3: Set the quantity of addresses to generate.
- Step 4: Copy the addresses in your preferred separator format.
Example
Input
Locally administered, unicast, quantity: 3
Output
02:4A:F3:B1:C8:7D 02:91:E2:5C:A0:F4 02:3D:88:12:7E:BC
Tips & Notes
- Use locally administered addresses (set bit 1 of the first byte) for virtual machines to avoid conflicts with real hardware OUIs.
- Avoid multicast MAC addresses for unicast traffic — they are reserved for group communication protocols like multicast IP.
- For testing with a known vendor OUI, look up the OUI using the mac-lookup tool first.
Frequently Asked Questions
Are generated MAC addresses unique?
With 48 bits of address space (281 trillion combinations) and random generation, collisions are extremely unlikely. However, generated addresses are not registered with IEEE and could theoretically conflict with real device addresses on the same network.
What is the difference between a universally and locally administered address?
A universally administered address (UAA) uses an OUI registered with IEEE to a specific organization. A locally administered address (LAA) has bit 1 of the first byte set to 1, signaling that it was assigned locally rather than by the manufacturer — safe to use in virtual environments.
MAC Address Generator
Generate random MAC addresses with a custom prefix, selectable delimiter, and uppercase or lowercase formatting.
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