To setup RARP, you need to know the Ethernet address (a.k.a. the MAC address) of the client computers to be installed. If you don't know this information, you can pick it off the initial OpenPROM boot messages, use the OpenBoot .enet-addr command, or boot into ``Rescue'' mode (e.g., from the rescue floppy) and use the command /sbin/ifconfig eth0. On a RARP server system using a Linux 2.2.x kernel, you need to populate the kernel's RARP table. To do this, run the following commands: /sbin/rarp -s client-hostname client-enet-addr /usr/sbin/arp -s client-ip client-enet-addr If you get SIOCSRARP: Invalid argument you probably need to load the RARP kernel module or else recompile the kernel to support RARP. Try modprobe rarp and then try the rarp command again. On a RARP server system using a Linux 2.4.x kernel, there is no RARP module, and you should instead use the rarpd program. The procedure is similar to that used under SunOS in the following paragraph. Under SunOS, you need to ensure that the Ethernet hardware address for the client is listed in the ``ethers'' database (either in the /etc/ethers file, or via NIS/NIS+) and in the ``hosts'' database. Then you need to start the RARP daemon. In SunOS 4, issue the command (as root): /usr/etc/rarpd -a; in SunOS 5, use /usr/sbin/rarpd -a.