Reverse Address Resolution Protocol (RARP) allows a device on a local area network (LAN) to discover its IP address. Here's a breakdown of how it works:
RARP Explained
RARP is a protocol used when a device knows its MAC address (physical address) but needs to learn its IP address. This is particularly useful for diskless machines that boot from a network.
The RARP Process
The process can be summarized in the following steps:
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RARP Request: A physical machine on the LAN broadcasts a RARP request packet. This packet contains the machine's MAC address and a request for its corresponding IP address.
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RARP Server: A specialized RARP server on the same LAN listens for these RARP requests.
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Address Lookup: Upon receiving a RARP request, the server looks up the IP address associated with the MAC address in its configuration table.
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RARP Response: The RARP server sends a RARP response packet back to the requesting machine, containing the IP address.
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IP Address Assignment: The requesting machine receives the RARP response and configures itself with the provided IP address.
Visual Representation
| Step | Action | Description |
|---|---|---|
| 1 | RARP Request Broadcast | Device sends out a RARP request containing its MAC address. |
| 2 | RARP Server Receives Request | RARP server on the LAN listens and receives the request. |
| 3 | IP Address Lookup | Server searches for the IP address associated with the MAC address. |
| 4 | RARP Response Sent | Server sends a RARP response containing the IP address. |
| 5 | IP Address Configuration | Device receives the response and configures its IP address accordingly. |
Key Aspects
- Local Area Network (LAN): RARP operates within a local network.
- RARP Server: Requires a dedicated server configured to respond to RARP requests. This server must reside on the same LAN as the requesting device.
- Physical Address (MAC): The protocol relies on the device already knowing its MAC address.
