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Commonly confused · Networking Fundamentals

MAC Address vs IP Address: What's the Difference?

A MAC address is a 48-bit Layer 2 hardware identifier assigned to a network interface and used for delivery within a local segment. An IP address is a Layer 3 logical address assigned by configuration and used to route traffic between networks.

MAC Address

Full definition
vs

IP Address

Full definition
MAC AddressIP Address
OSI layerLayer 2 (Data Link)Layer 3 (Network)
Length48 bits, 12 hex digits32 bits (IPv4) or 128 bits (IPv6)
Assigned byManufacturer (OUI plus serial); can be spoofed or randomizedAdministrator, DHCP, or SLAAC
ScopeLocal segment only; rewritten at every router hopEnd to end across networks
StructureOUI (vendor) plus device identifierNetwork portion plus host portion
Related lookupARP finds the MAC for a known IPv4 addressDNS finds the IP for a known name
Remember it

The MAC is your name tag in the room; the IP is your mailing address in the world.

Exam tip

A classic question asks what changes as a packet crosses a router: the source and destination MAC addresses change at each hop while the IP addresses stay the same (absent NAT).

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