MAC Address vs IP Address: What’s the Difference?
Learn the differences between MAC and IP addresses, how each operates at different network layers, and why you need both.
MAC vs. IP: Two Types of Addresses
A MAC (Media Access Control) address is a hardware identifier assigned to a network interface card (NIC). It operates at Layer 2 (the data link layer) of the OSI model and is typically unique to each physical or virtual interface.
An IP (Internet Protocol) address, by contrast, operates at Layer 3 (the network layer) and identifies a device’s location on an IP network. While MAC addresses are tied to hardware, IP addresses are assigned and can change as a device moves between networks.
How MAC and IP Addresses Work Together
When a device wants to send data to another host on the same local network, it uses the Address Resolution Protocol (ARP) to map the destination IP address to a MAC address. Frames on the local segment use MAC addresses to reach the correct interface, while IP addresses ensure packets can be routed across different networks.
Routers strip and recreate Layer 2 headers as packets move between segments, but the Layer 3 IP addresses remain consistent end to end, enabling scalable routing across the internet.
Practical Implications for Troubleshooting and Security
Understanding the distinction helps with tasks like configuring DHCP reservations (which bind IPs to specific MAC addresses), filtering access on routers and switches, and interpreting network logs. MAC addresses are useful for identifying specific devices on local networks, while IP addresses are more relevant for routing, firewall rules, and geolocation.
Security tools and policies may reference both: for example, blocking a MAC address on Wi‑Fi to keep a device off your network and blocking an IP address at the firewall to stop traffic from a hostile host.