CompTIA Tech+ (FC0-U71)InfrastructureMedium
A network technician is troubleshooting a connectivity issue and needs to identify the unique hardware identifier that is permanently assigned to a computer's network interface card by the manufacturer. Which identifier should the technician check?
- ADefault gateway
- BMAC address
- CIP address
- DSubnet mask
Show answer & explanationAnswer & explanation
Correct answer: B. MAC address
A MAC (Media Access Control) address is a unique, hardware-burned identifier assigned by the NIC manufacturer, used for local network communication at Layer 2. IP addresses, subnet masks, and default gateways are logical network configuration values that can change.
Why the other options are wrong
- A. A default gateway is the router address used to reach other networks, not a device identifier.
- C. An IP address is a logical address that can be reassigned or changed via DHCP.
- D. A subnet mask defines the network and host portions of an IP address, not a device identifier.
MAC Address
A unique 48-bit hardware identifier burned into a network interface card by its manufacturer, used for local network communication.
- Typically written as six pairs of hexadecimal digits (e.g., 00:1A:2B:3C:4D:5E)
- Operates at Layer 2 (Data Link) of the OSI model
- Unlike IP addresses, it generally does not change
Memory trick: MAC = 'Manufacturer's Address Card' burned in forever.