Probably a stupid question IP Address and MAC Address

Pest-Aside asked 2 years ago

We have a couple of computers on our work network that use up excessive bandwidth (I am from Malaysia, so the quality of internet is not fast).

To limit access to our network, we need to enter in the IP address of the computer we want to block, but unfortunately our router only gives us the MAC addresses of the computers on our network.

Is there anyway to convert a MAC address into an IP address?

Sorry for such a question.

1 Answers
Rob Vargas Staff answered 2 years ago

Basically, yes. The precise steps depend on how much you have access to the hardware on your network.

Basically, there's an underlying protocol called ARP (Address Resolution Protocol). ARP (basically) tracks the network path to a device by MAC Address. "IP Address xxx.xxx.xxx.xxx is accessible via MAC Address XX:XX:XX:XX:XX:XX" and so on. But ARP only records the first "hop" from where you read that entry.

Because of that, you have to look through the ARP entries (called an ARP Table) of each device in the path until you find the device pointing directly at the target MAC address.

Another option, if you manage DHCP on your network, is to look at DHCP. I believe that DHCP records the MAC address of a device (computer, switch, etc) that requests an IP address.

Hope that helps.

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