ARP (Address Resolution Protocol) is a network protocol used to map an IP address (logical address) to a MAC address (physical address) within a local area network (LAN). It is a critical component of communication in IPv4 networks, allowing devices to locate and communicate with each other on the same subnet.
How ARP Works:
- A device sends an ARP Request broadcast on the network, asking, “Who has this IP address?”
- The device with the corresponding IP address responds with its MAC address in an ARP Reply.
- The requesting device stores this information in its ARP cache for future use.
Key Features:
- Layer 2 and Layer 3 Interaction: Operates between the data link layer (MAC addresses) and the network layer (IP addresses) of the OSI model.
- Broadcast-Based: ARP requests are sent to all devices on the local network.
- Temporary Caching: ARP caches store address mappings temporarily to reduce network traffic.
Common Use Cases:
- Resolving IP addresses to MAC addresses for devices in the same subnet.
- Enabling communication between devices on Ethernet networks.
Security Concerns:
ARP is vulnerable to attacks like ARP spoofing, where an attacker manipulates the ARP table to intercept or redirect network traffic.
ARP is a foundational protocol that ensures efficient communication within a local network by linking logical IP addresses with physical MAC addresses.
