What this means
The IEEE assigned the MA-M block 18C3F43 to General Test Systems. Every network interface they manufacture under this block has a MAC address beginning with these digits, followed by a unique per-device identifier. If a device on your network shows a MAC starting 18:C3:F4:3, it is General Test Systems hardware.
Frequently Asked Questions
Who owns MAC prefix 18C3F43?
18C3F43 is registered to General Test Systems in the IEEE MA-M registry.
What does the MA-M registry type mean?
An MA-M assignment covers 28 bits of the address, giving the vendor 1,048,576 device addresses, a quarter of a full MA-L block. General Test Systems's block covers 1,048,576 addresses.
What devices use 18C3F43?
Any network device with a MAC address starting 18:C3:F4:3 was manufactured by or for General Test Systems.