All network devices have a unique hardware identifier, also referred to as the MAC address. To find the MAC address of a network device, you can employ a utility program for your specific network operating system, based on the type of network device involved.
Displaying the MAC Address on your System or Device
Based on the operating system (OS) installed on your machine, there are different utilities which can help find the MAC address:
1. Find the MAC Address on a Windows Computer – The MAC address of a device running on Windows can be displayed through the ipconfig utility. Older versions of Windows including Windows 95 and Windows 98 offer the winipcfg to view the MAC address.
When more than one MAC address is displayed on a single device, each of the MAC addresses in the list refers to one of the network cards installed on the system. Also, sometimes, virtual MAC addresses might be displayed, as in the case of dial-up network connections or VPN clients.
Newer versions of Windows also allow the MAC address to be modified through the My Network Places interface. The procedure works on the condition that the required software support is also built into the adapter driver.
2. Display the MAC Address on Unix or Linux Systems – In a Linux or Unix system, you can find the MAC address in the boot message sequence, right from the screen during the regular reboot process.
The MAC address can also be obtained from the boot messages queued in the log file, from “/var/log/messages” or “/var/adm/messages.”
Some versions of Unix and Linux also support the ipconfig –a command line utility for displaying the MAC address.
3. Access the MAC Address on a Mac System – An Apple Mac system features a TCP/IP control panel, where the Mac address can be displayed on either the “Info” screen or the “User Mode / Advanced” screens for a system running Open Transport.
For systems running MacTCP, the MAC address is displayed under the “Ethernet” icon.
Changing the MAC Address of Your System
Even though MAC addresses do not require to be altered, and are fixed in nature, certain scenarios might require you to change the MAC address, as outlined below:
Changing MAC Address to Work with Your ISP
Even when most Internet subscriptions come with a single fixed IP address assignment per customer, this approach might not be as efficient. An ISP, therefore, assigns a dynamic IP address to a customer, which changes every time the client tries to connect to the Internet.
Assigning a login name and password for a dial-up connection or tracking the MAC address, as in the case of cable modem providers ensures that each customer has a single IP address.
In the case of ISP, however, the MAC address monitoring looks for the same MAC address value that was assigned to the device interfacing with the ISP initially. This device can either be a cable modem, broadband router or PC, which may have an attached network.
However, when the customer replaces this device or its adapter, the value no longer coincides with the initially supplied MAC address. In such a scenario, the MAC address might need to be replaced to make sure that the ISP does not disable your connection on the grounds of security.
Changing MAC Address through Cloning
Sometimes, a MAC address might need to be updated. However, physically updating the address through a request placed with your ISP may take time which results in loss of service for a period.
Another alternative to this approach is to use cloning. In the process of cloning, a new device is setup with a new MAC address, which matches the original device. MAC address cloning is an advanced configuration option, and an address identical to the initial address is available to your ISP. Different types of routers have their configuration scenarios, available through their associated documentation.
Changing MAC Address to Work with Your Cable Modem
Your MAC address might also be tracked by the cable modem connected to your network. This means that when you change the system or its network adapter, the change reflected in the MAC address might cause the connection to stop functioning.
The solution is resetting both the computer and the cable modem through a soft reset or power cycling to automatically change the MAC address which is stored in the modem.
MAC addresses are the necessary component in networking which ensures smooth functioning of the TCP/IP protocol. As outlined above, operating systems and routers allow you to view and change MAC addresses when the need arises. You might want to change the MAC address to make sure your Internet connection works well and in some cases ensure that the necessary privacy constraints are enforced.