Arp and Rarp are query/lookup protocols only. They either lookup MAC from IP address (Arp) or lookup IP address from MAC (Rarp) but neither can actually assign anything. Even Rarp is useless unless the laptop or some other device has actually very recently communicated with the appliance so that the IP address is in the Arp cache. DHCP, BOOTP or manual configuration are the only 3 ways to get an IP configuration on to that device.