Which is the correct command to change the MAC address for an Ethernet adapter in a Unix-based system?

In Unix-based systems (e.g., Linux), the ifconfig command is historically used to configure network

interfaces, including changing the Media Access Control (MAC) address of an Ethernet adapter. The

correct syntax to set a new MAC address for an interface like eth0 is ifconfig eth0 hw ether

AA:BB:CC:DD:EE:FF, where hw specifies the hardware address type (ether for Ethernet), followed by

the new MAC address in colon-separated hexadecimal format.

Why A is correct: The hw ether argument is the standard and correct syntax recognized by ifconfig to

modify the MAC address. This command temporarily changes the MAC address until the system

reboots or the interface is reset, assuming the user has sufficient privileges (e.g., root). CNSP

documentation on network configuration and spoofing techniques validates this syntax for testing

network security controls.

Why other options are incorrect:

B: hdw is not a valid argument; it’s a typographical error and unrecognized by ifconfig.

C: hdwr is similarly invalid; no such shorthand exists in the command structure.

D: hwr is incorrect; the full keyword hw followed by ether is required for proper parsing.

Reference: CNSP "Network Interface Configuration" (Section on MAC Address Manipulation)

confirms ifconfig eth0 hw ether as the standard command, noting its use in penetration testing for

spoofing scenarios.