Internet, Networking, & Security Home Networking How to Find and Change a MAC Address MAC addresses are meant to be permanent, but you can change them By Bradley Mitchell Writer An MIT graduate who brings years of technical experience to articles on SEO, computers, and wireless networking. our editorial process LinkedIn Bradley Mitchell Updated March 07, 2020 pxhere Home Networking The Wireless Connection Routers & Firewalls Network Hubs ISP Broadband Ethernet Installing & Upgrading Wi-Fi & Wireless Tweet Share Email The method used to find a MAC address depends on the type of network device involved. All popular network operating systems contain utility programs that allow you to find (and sometimes change) MAC address settings. A MAC (media access control) address consists of six pairs of hexadecimals and identifies hardware on a network. Manufacturers embed this unique number at the time of manufacture or store it in the firmware. It's generally not meant to be changed. Find a MAC Address in Windows Use the ipconfig utility (with the /all option) to display the computer's MAC address in modern versions of Windows. Older versions of Windows (Windows 95 and Windows 98) used the winipcfg utility. Both winipcfg and ipconfig may display multiple MAC addresses for one computer. One MAC address exists for each installed network card. Additionally, Windows maintains one or more MAC addresses that are not associated with hardware cards. For example, Windows dial-up networking uses virtual MAC addresses to manage the phone connection as if it were a network card. Some Windows VPN clients have their own MAC addresses. The MAC addresses of these virtual network adapters are the same length and format as true hardware addresses. Find a MAC Address in Unix or Linux The specific command used in Unix to find a MAC address varies depending on the version of the operating system. In Linux and in some forms of Unix, the command ifconfig -a returns MAC addresses. MAC addresses in Unix and Linux are also found in the boot message sequence. These operating systems display the computer's MAC address onscreen as the system reboots. Additionally, boot-up messages are retained in a log file (usually var/log/messages or /var/adm/messages). Find a MAC Address on a Mac To find MAC addresses on Apple Mac computers, click System Preferences > Network > Advanced > Hardware. If the computer runs Open Transport, the MAC address appears under the Info or User Mode/Advanced screens. If the system runs MacTCP, the MAC address appears under the Ethernet icon. Summary: How to Find a MAC Address In summary, here's how to find a computer's MAC address: Windows: ipconfig/all, or winipcfgLinux and some Unix: ifconfig -a (note the first "f" in ifconfig; this is easy to confuse with Windows' ipconfig)Macintosh: Settings > Network > Advanced > Hardware MAC addresses are fixed numbers that cannot be changed. However, there are several valid reasons to change a MAC address. Change a MAC Address to Work With Your ISP Most internet subscriptions provide the customer with a single IP address. The internet service provider (ISP) may assign one static (fixed) IP address to each customer. This approach, however, is an inefficient use of IP addresses. The ISP more commonly issues each customer a dynamic IP address that changes each time the customer connects to the internet. ISPs ensure each customer receives only one dynamic address using several methods. Dial-up and many DSL services typically require the customer to log in with a username and password. Cable modem services, on the other hand, do this by registering and tracking the MAC address of the device that connects to the ISP. The device with the MAC address that is monitored by an ISP can be the cable modem, a broadband router, or the PC that hosts the internet connection. The customer is free to build a network behind this equipment, but the ISP expects the MAC address to match the registered value at all times. When a customer replaces that device, however, or changes the network adapter inside it, the MAC address of the new equipment will no longer match the one registered at the ISP. In this case, the ISP typically disables the customer's internet connection for security (and billing) reasons. Although MAC addresses do not reveal geographic location information as IP addresses do, changing MAC addresses can increase internet privacy in some situations. Change a MAC Address Through Cloning Some people contact their ISPs to request they update the MAC addresses associated with their subscriptions. This process works but takes time, and internet service is unavailable until the provider takes action. To quickly work around this problem, change the MAC address on the new device so that it matches the address of the original device. Although you cannot change a physical MAC address in hardware, you can emulate it in software. This process is called cloning. Many broadband routers support MAC address cloning as an advanced configuration option. The emulated MAC address appears to the service provider as identical to the original hardware address. The specific procedure of cloning varies depending on the type of router; consult the product documentation for details. MAC Addresses and Cable Modems In addition to MAC addresses tracked by ISPs, some broadband modems also track the MAC address of the host computer's network adapter within the home network. If you swap the computer connected to the broadband modem or change its network adapter, your internet connection might not function afterward. In this case, MAC address cloning is not required. Resetting (including recycling power) on both the cable modem and the host computer will change the MAC address stored inside the modem automatically. Change MAC Addresses Through the Operating System Windows offers an easy way to change MAC addresses. Press Windows key+X, then select Device Manager. Expand the Network adapters list. Right-click the adapter whose MAC address you'd like to change, then select Properties. Select the Advanced tab. Select Locally Administered Address or Network Address, then choose Value. Clear the existing value, enter a new address without hyphens, then select OK. Restart the computer. In Linux and Unix In Linux and some versions of Unix, ifconfig supports changing MAC addresses if the necessary network card and driver support exist.