Address Resolution Protocol Proxy

Information About Address Resolution Protocol

The address resolution protocol (ARP) is a protocol used by the Internet Protocol (IP) [RFC826], specifically IPv4, to map IP network addresses to the hardware addresses used by a data link protocol. When a wireless client sends an ARP request for an IP address of interest, the controller performs a search for that address in its database. If an entry is found in the controller database, then the ARP is converted to unicast and forwarded to that particular client. If there is no entry in the controller’s database, the ARP request is flooded out to the VLAN wired ports.

Configure Address Resolution Protocol Proxy (CLI)

ARP Proxy is the ability of the controller to respond to the ARP request packet destined for the wireless clients. During broadcast suppression, the controller checks if proxy is enabled for the destined wireless clients. If proxy is enabled, the controller drops the ARP request packet and generates a response to the source of the ARP request in a way that the packet appears to be coming from the wireless client. This helps in limiting the traffic to the wireless clients.

If ARP Proxy is not enabled, the broadcast ARP request is converted into an unicast ARP request with the MAC address of the target client, and is forwarded to only that client.


Note

  • Proxy ARP is applicable only in central switching mode.

  • A device will not proxy the ARP request if the destination address is not that of a wireless client.

Procedure

  Command or Action Purpose

Step 1

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 2

wireless profile policy policy-profile-name

Example:

Device(config)# wireless profile policy policy-profile1

Configures a WLAN policy profile and enters wireless policy configuration mode.

Step 3

ipv4 arp-proxy

Example:

Device(config-wireless-policy)# ipv4 arp-proxy

Enables ARP proxy.