Micro Tools
Advertisement

MAC Address Generator

Generate random MAC addresses for virtual machines, containers, lab networks and testing. Control the separator style, letter case, the locally-administered bit, and optionally pin the vendor OUI prefix.

MAC address options

Unicast addresses, safe for VMs and labs.

Press Generate MACs.

Everything runs locally. Nothing is sent to any server.

Advertisement

MAC address structure

A MAC address is 48 bits, usually shown as six hex pairs. Two bits in the first byte are special: the multicast bit (least significant) marks group addresses, and the U/L bit (second least) marks locally administered addresses. This tool always clears the multicast bit for unicast addresses and can set the U/L bit, which is the correct practice for virtual machines, containers and test devices.

What they are used for

Random MACs are used for VM and container networking, network simulation, DHCP testing and privacy (MAC randomization). Optionally pin the first three bytes to a vendor OUI to mimic a specific manufacturer, or leave them random. Never use a generated MAC to impersonate another device on a network you do not own.

Related tools

JSON formatterFormat and validate JSON, privately. Regex testerTest regex live with highlighting. Base64 encoderBase64 encode and decode, plus URL encoder and JWT decoder.

MAC Address Generator FAQs

What is the OUI prefix option?
The first three bytes (OUI) identify the manufacturer in real addresses. This tool can pin them to a vendor you type, or randomize everything. The remaining three bytes are always random.
What does locally administered mean?
The U/L bit marks an address as locally administered, which is the correct setting for virtual machines, containers and test gear. Real hardware from a factory has this bit cleared.
Is it legal to use a random MAC?
Yes for virtual machines, containers, lab networks and software testing. No for impersonating someone else's device on a network you do not manage, which can break networks and violate policies.
Why must the first byte be even?
If the first byte is odd (for example ending in 1, 3, 5), the multicast bit is set. Unicast addresses must have an even first byte. This tool always generates unicast addresses.
Which separator format should I pick?
Set the separator to none for 12 plain hex characters, common in embedded configs, or to dashes for the Windows-style format. Colons are the most widely used.
Advertisement