Name

ip proxy-arp — interface

Synopsis

ip proxy-arp
no ip proxy-arp

Configures

The proxy-arp feature for an interface

Default

Enabled

Description

ARP allows machines to find hardware addresses (MAC addresses) using the corresponding IP addresses. The router’s proxy-arp feature helps the machines find each other across subnets. When a host sends an ARP packet requesting information about a host that can’t receive the ARP broadcast, the router helps out by responding to the ARP packet on behalf of the requested host.

While proxy-arp is often useful, it can be a burden on the router in large networks. Disabling proxy-arp and relying on proper subnetting is a better solution than relying on proxy-arp to solve subnetting problems.

Example

The following commands disable proxy-arp on ethernet0. All hosts on this subnet must have the proper subnet mask because proxy-arp isn’t there to help them.

interface ethernet0
  ip address 10.10.1.64 255.255.255.224
  no ip proxy-arp

Get CISCO IOS in a Nutshell now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.