O'Reilly logo

Cisco IOS in a Nutshell, 2nd Edition by James Boney

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

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

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required