Tag: MAC address

All about MAC addresses: what are they for, how to view and find out the manufacturer by MAC address

A media access control address (MAC address) of a computer is a unique identifier assigned to network interfaces for communications at the data link layer of a network segment. MAC addresses are used as a network address for most IEEE 802 network technologies, including Ethernet and Wi-Fi.

MAC addresses are most often assigned by the manufacturer of a network interface controller (NIC) and are stored in its hardware, such as the card's read-only memory or some other firmware mechanism. If assigned by the manufacturer, a MAC address usually encodes the manufacturer's registered identification number and may be referred to as the burned-in address (BIA). It may also be known as an Ethernet hardware address (EHA), hardware address or physical address (not to be confused with a memory physical address). This can be contrasted to a programmed address, where the host device issues commands to the NIC to use an arbitrary address (https://en.wikipedia.org/wiki/MAC_address).

If MAC-address is known, you are able to lookup it that allows you to easily find the company details (company name, address, and country) according to the MAC address of a product.

How to determine the manufacturer of the device by MAC address

In Windows, there is a free program MACAddressView to determine the vendor (manufacturer) of a device by MAC address.

You can search by MAC address, company name, company address, company country, all MAC addresses. The input rules are as follows:

  • Enter one or more MAC addresses, separated by spaces or by pressing <Enter>. You can specify the complete address (for example, 01-02-03-04-05-06) or only its first 3 bytes (for example, 01-02-03).
  • Enter one or more company names to search for, separating each search string with <Enter>.
  • Enter one or more addresses to search, separating each search string with <Enter>.
  • Enter one or more countries to search for, separating each search string with <Enter>.

How to find my MAC address

On Windows, you can find out your MAC address in several ways – from the GUI and from the command line.

To find out your MAC address, open Control Panel → Network and Internet → Network and Sharing Center → Change adapter settings or you can just run the command:

ncpa.cpl

Select the adapter (network connection) you are interested in, right-click on it and select “Status” in the context menu. Then click the “Details…” button:

In the window that opens, the item “Physical Address” is the MAC address of this network adapter:

To find out your MAC address in Windows from the command line, open a command prompt, to do this press Win+x and select “Windows PowerShell”. You can use two commands, the first one

getmac

shows brief information about all the MAC addresses of the system, while it is not always easy to map an interface to specific matching MAC address.

Command

ipconfig /all

displays more advanced information about the connection, using it you can navigate which physical address (MAC) belongs to which interface:

How to find the MAC address of devices on the local network

Using the nmap program, both in Windows and in Linux, you can find devices connected to the local network and find out their MAC addresses. Example command for subnet 192.168.0.0/24:

sudo nmap -sn -n 192.168.0.0/24

How to find the MAC address and manufacturers of wireless access points

You can find out which Wi-Fi networks are working near you, as well as find out their manufacturer using the WifiInfoView program.

WifiInfoView scans wireless networks in range and displays extended information about them, including: network name (SSID), MAC address, PHY type (802.11g or 802.11n), RSSI, signal quality, frequency, channel number, maximum speed, company name , router model and router name (only for routers that provide this information) and more.

Pay attention to the columns “Router Model” and “Router Name”, for some routers (which send this information themselves) the exact model is written in them.

Lookup MAC-address to find device manufacturer online

If you know the MAC address and you want to know the manufacturer of this device, you can use the free online service to query the database: https://w-e-b.site/?act=mac

Why does VirtualBox lose connection when changing MAC address (SOLVED)

Virtual machine, after changing MAC address of eth0, the connection does not work. When changing only the last three octets, the situation is the same. Restarting the modem does not give results, there is no filtering by MAC addresses. Why is this happening and how can I fix it?

VirtualBox does not support changing the MAC address inside the guest virtual machine.

The “official” method of operation is to change the address in the virtual machine settings when the guest computer is completely turned off.

Guest MAC address information is generated by the physical hardware, in this case the VirtualBox network adapter.

VirtualBox uses the hardware on the host and provides the MAC address for the guest as if it were in metal. But a reasonable question arises, because on a physical computer, the MAC address is also hard-coded into the network card and it is impossible to change it on it, but Linux supports changing the MAC address to arbitrary ones and the network is working fine, why is there such a difference?

And by the way, changing the MAC address in the virtual machine breaks the Internet connection for the wired interface only. For Wi-Fi wireless network interfaces (connected via USB), changing the MAC address does not lead to any problems, they work fine, there is a network connection.

There are two possible reasons for this behavior:

1. Whatever MAC address is hard-coded into the network card, the final decision whether or not to accept a packet is made by the operating system kernel. This is in the case of a physical computer. In the case of a virtual machine, it is up to VirtualBox, which may not be aware of what exactly is happening in the virtual machine and that it has changed its MAC address. Therefore VirtualBox does not know about the new MAC address and does not forward Ethernet frames to it.

2. The differences between wired and wireless networks are obvious: in wireless networks, radio waves propagate freely and every device within reach has access to absolutely all transmitted frames. As for the wired network, the sender sends Ethernet frames to a specific port (in the sense of the device's network port). That is, it is possible that the data is simply not sent by the sender to the new MAC address, since it does not know anything about it.

However, some users wrote that they managed to get the wired interface in the virtual machine to work after changing the MAC address - for this they put it in promiscuous mode. This method did not work for me (the network is still unavailable), but you can try it yourself (replace the eth0 interface name with your own):

sudo macchanger -s eth0 # check the current MAC address
sudo macchanger -r eth0 # change the MAC address to random
sudo ip link set dev eth0 promisc on # put the network interface in promiscuous mode
ping 8.8.8.8 # check if the network is working
# sudo macchanger -p eth0 # return the old MAC address if the network is down

As for the wireless interfaces in the virtual machine, everything works there without the need to switch the network interface to promiscuous mode.

Commands for changing the MAC-address of the Wi-Fi card (replace the wlan0 interface name with your own):

sudo ip link set dev wlan0 down # this is required
sudo macchanger -s wlan0 # check the current MAC address
sudo macchanger -r wlan0 # change the MAC address to random
sudo ip link set dev wlan0 up # this is required
# sudo macchanger -p wlan0 # if needed, return the old MAC address
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