Cabletron Systems 9032578-05 manual Configuring Reverse Address Resolution Protocol Rarp

Chapter 8: IP Routing Configuration Guide

When you enable packets to be dropped for hosts with unresolved MAC addresses, the SSR will still attempt to periodically resolve these MAC addresses. By default, the SSR sends ARP requests at 30-second intervals to try to resolve up to 50 dropped entries.

To change the interval for sending ARP requests for unresolved entries to 45 seconds:

ssr# arp set unresolve-timer 45

To change the number of unresolved entries that the SSR attempts to resolve to 75:

ssr# arp set unresolve-threshold 75

Configuring Proxy ARP

The SSR can be configured for proxy ARP. The SSR uses proxy ARP (as defined in RFC 1027) to help hosts with no knowledge of routing determine the MAC address of hosts on other networks or subnets. Through proxy ARP, the SSR will respond to ARP requests from a host with a ARP reply packet containing the SSR MAC address. Proxy ARP is enabled by default on the SSR. The following example disables proxy ARP on all interfaces:

ssr(config)# ip disable-proxy-arp interface all

Configuring Reverse Address Resolution Protocol (RARP)

Reverse Address Resolution Protocol (RARP) works exactly the opposite of ARP. Taking a MAC address as input, RARP determines the associated IP address. RARP is useful for X- terminals and diskless workstations that may not have an IP address when they boot.

They can submit their MAC address to a RARP server on the SSR, which returns an IP address.

Configuring RARP on the SSR consists of two steps:

1.Letting the SSR know which IP interfaces to respond to

2.Defining the mappings of MAC addresses to IP addresses

82 SmartSwitch Router User Reference Manual