Radio Shack FC-241 Configuring a Router as a Rarp Server, Configures the router as a Rarp server

Configuring Additional File Transfer Functions

Configuring a Router as a Server

Configuring a Router as a RARP Server

Reverse Address Resolution Protocol (RARP) is a protocol in the TCP/IP stack that provides a method for finding IP addresses based on MAC (physical) addresses. This functionality is the reverse of broadcasting Address Resolution Protocols (ARPs), through which a host can dynamically discover the MAC-layer address corresponding to a particular IP network-layer address. RARP makes diskless booting of various systems possible (for example, diskless workstations that do not know their IP addresses when they boot, such as Sun workstations or PCs on networks where the client and server are on separate subnets). RARP relies on the presence of a RARP server with cached table entries of MAC-layer-to-IP address mappings.

You can configure a Cisco router as a RARP server. This feature enables the Cisco IOS software to answer RARP requests.

To configure the router as a RARP server, use the following command in interface configuration mode:

Command	Purpose
ip rarp-server ip-address	Configures the router as a RARP server.

Figure 16 illustrates a network configuration in which a router is configured to act as a RARP server.

Figure 16 Configuring a Router as a RARP Server

Sun server 172.30.3.100

E1 172.30.3.4

Router A

E0 172.30.2.4

Sun workstation
172.30.2.5	S1495a
Mac address
0800.2002.ff5b

Cisco IOS Configuration Fundamentals Configuration Guide, Release 12.1

FC-246