Taking into account that it is possible to determine the IP address if you know the MAC address of a computer, those looking for total anonymity should also consider changing their MAC address. Learn how to change MAC address.

If you don’t know what a Media Access Control (MAC) address is considered reading this Wikipedia article.

Determining IP Address from MAC Address

Computers can determine the IP address from MAC address using DHCP and other protocols like Address Resolution Protocol. DHCP  Manages network configuration by registering and updating IP addresses and DNS names. Learn how you can do the same thing.

No universal tool to get the IP address from MAC

An end user can not easily determine an IP address given a known MAC address. It can be done in certain specific situations, but there is no such universal tool to get the IP from the MAC address.

The Address Resolution Protocol (Formerly known as ARP) allows a host to find the MAC address of a node with an IP address on the same physical network when given the node’s IP address. To make ARP efficient, each computer caches IP-to-MAC address mappings to eliminate repetitive ARP broadcast requests.

The ARP tool allows a user to view and modify Address Resolution Protocol table entries on the local computer. The command is useful for viewing the Address Resolution Protocol cache and resolving address resolution problems.

In order to use ARP tool open the Command Prompt and type

arp -a

and you will get a list of all the connected devices on your network along with their physical addresses!

IP Address from MAC Address

MAC-to-IP mapping systems

Some large networks managed globally to solve the problem of mapping MAC-to-IP address by installing special management software agents on all computers. These software systems are based on Simple Network Management Protocol (SNMP) and include the capability called network discovery.

These systems forward messages out to the agent on every network device a request for both the IP and MAC addresses of that device. The system receives then stores the results in a master table separate from any individual ARP cache.

Network discovery can also be implemented (with Internet Protocol) using ping commands and ICMP (Internet Control Message Protocol) messages. When pinging a remote device from any client an ARP cache update is triggered. This update occurs only in the Address Resolution Protocol cache of the LAN routers and not on the originating client, however.

Other useful tools to get the IP address from MAC

Finally, you can use a free program to get an IP address from a MAC address. It’s called CC Get MAC Address and it can be downloaded here.

Another free program is the one called Advanced IP Scanner. It is a program totally dedicated to scanning IP addresses and will do the same thing as CC Get MAC Address.

After running IP Scanner and simply run the arp –a command to get a list of IP/MAC Addresses.

How to change MAC address

Now, let’s see how you can change it. The solution is simple as it can be done using the free application Technitium MAC Address Changer. It allows you to change Media Access Control (MAC) Address of your Network Interface Card (NIC) or Wireless Network Card (WiFi), irrespective of the NIC’s drivers or its manufacturer.

Change Mac Address - Techtinium MAC Changer

Every NIC has a MAC address hard coded in its circuit by the manufacturer. This hard coded MAC address is used by windows drivers to access Ethernet Network (LAN). This tool can set a new MAC address to your NIC, bypassing the original hard coded MAC address.

How to change MAC Address with Technitium MAC Address Changer

  1. Download Technitium MAC Address Changer
  2. Start MAC Address Changer. You will see all available network adapters (the top list).
  3. Select the adapter you want to change the MAC address. You will get the details of your selection below.
  4. Click Change MAC button, enter new MAC address and click Change Now button and confirm changes.
  5. To restore the original MAC address of the network adapter, select the adapter, click Change MAC button and then click Original MAC button and confirm changes you made when prompted.

How Does It Work?

This tool does not modify the MAC address from your NIC card, it just writes a value into the Windows registry.

When the Network Adapter Device is enabled, Windows searches for the registry value ‘NetworkAddress‘ in the key: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E972-E325-11CE-BFC1- 08002bE10318}\[ID of NIC e.g. 0001].

If a value is present, Windows will use it as MAC address, if not, Windows will use the hard coded manufacturer provided MAC address.

Technitium MAC Address Changer works with all Windows versions including Vista and Windows 7.

>> Technitium MAC Address Changer