MAC address in DHCP client list different from manufacturer’s. Also, same device getting two different MAC addresses

dhcpip addressmac addressnetworkingrouter

here is my problem… I’m managing my local Wi-Fi network and I wanted to reserve some IP addresses to important devices, such as the local printer in my house. It’s a simple task. I only needed to know my printer’s MAC address and reserve it to a specified IP address (192.168.1.50) within my routers configuration interface. The problem is that I checked my DCHP clients list and I noticed that many of the devices listed didn’t have the correct MAC address. In fact, they were slightly modified. For example: My printer’s MAC address (the real one printed on its back) is C4-34-6B-2D-5E-04. In my router’s webpage, my printer’s MAC address is 02-0F-B5-2D-5E-04. For some reason, my router changed the first 6 numbers, so my address reservation couldn’t work. The same thing happened to some of my other devices. Their MAC address in my routers interface client list is not the same specified by the manufacturer. The first 6 numbers were also changed to 02-0F-B5-XX-XX-XX. Here is what my client list looks like:

DHCP Clients List

Notice that many of them have their MAC address’ first 6 numbers changed to 02-0F-B5… and the rest being correct. Also, something very strange, sometimes I get the same client getting two MAC addresses. One is slightly modified (6 first numbers) and the other one actually corresponds to the real MAC address. For example, look at clients ID 2 and 6. They have the same Client Name but different MAC Addresses. Would you know why this is happening? Sometimes, when I reboot the devices, the real MAC address is listed and so my address reservation works, but it’s kind of random. My router’s model is a TP-link TL-WR1043ND. Thanks everyone!

Best Answer

Thank you for your comments. Yeah, as a matter of fact I do have a NEGEAR WiFi extender. It’s the WN3000RPv3 in the picture. Its MAC address is slightly modified as well (first 6 numbers). Your comments made me notice that all devices connected to the network through my WiFi extender are the ones whose MAC addresses were modified. I checked NETGEAR website and I found this in the FAQ:

"I reserved some IP addresses for some devices on my router but devices no longer work when I connect them to the extender. What can I do?

The first 3 bytes of MAC address is translated into 02:0F:B5 as mentioned above. Please log into router and add translated MAC addresses into IP reservation list."

Problem solved then. It was indeed a virtual MAC address given to the device by the wifi extender. Thank you very much for your help!

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