Chapter 23 Configuring Dynamic ARP Inspection

Configuring Dynamic ARP Inspection

For configuration guidelines for rate limiting trunk ports and EtherChannel ports, see the “Dynamic ARP Inspection Configuration Guidelines” section on page 23-6.

Beginning in privileged EXEC mode, follow these steps to limit the rate of incoming ARP packets. This procedure is optional.

 

Command

Purpose

Step 1

 

 

configure terminal

Enter global configuration mode.

Step 2

 

 

interface interface-id

Specify the interface to be rate-limited, and enter interface configuration

 

 

mode.

 

 

 

Step 3 ip arp inspection limit {rate pps [burst

Limit the rate of incoming ARP requests and responses on the interface.

 

interval seconds] none}

The default rate is 15 pps on untrusted interfaces and unlimited on

 

 

 

 

trusted interfaces. The burst interval is 1 second.

 

 

The keywords have these meanings:

 

 

For rate pps, specify an upper limit for the number of incoming

 

 

packets processed per second. The range is 0 to 2048 pps.

 

 

(Optional) For burst interval seconds, specify the consecutive

 

 

interval in seconds, over which the interface is monitored for a high

 

 

rate of ARP packets.The range is 1 to 15.

 

 

For rate none, specify no upper limit for the rate of incoming ARP

 

 

packets that can be processed.

Step 4

 

 

exit

Return to global configuration mode.

Step 5

 

 

errdisable detect cause arp-inspection

(Optional) Enable error recovery from the dynamic ARP inspection

 

and

error-disabled state, and configure the dynamic ARP inspection recover

 

mechanism variables

 

errdisable recovery cause

 

By default, recovery is disabled, and the recovery interval is 300

 

arp-inspection

 

seconds.

 

and

 

For interval interval, specify the time in seconds to recover from the

 

errdisable recovery interval interval

 

error-disabled state. The range is 30 to 86400.

Step 6

 

 

exit

Return to privileged EXEC mode.

 

 

 

Step 7 show ip arp inspection interfaces

Verify your settings.

 

show errdisable recovery

 

Step 8

 

 

copy running-config startup-config

(Optional) Save your entries in the configuration file.

 

 

 

To return to the default rate-limit configuration, use the no ip arp inspection limit interface configuration command. To disable error recovery for dynamic ARP inspection, use the no errdisable recovery cause arp-inspectionglobal configuration command.

Performing Validation Checks

Dynamic ARP inspection intercepts, logs, and discards ARP packets with invalid IP-to-MAC address bindings. You can configure the switch to perform additional checks on the destination MAC address, the sender and target IP addresses, and the source MAC address.

 

 

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

 

 

 

 

 

 

OL-9775-02

 

 

23-11

 

 

 

 

 

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Image 549
Cisco Systems 3750E manual Performing Validation Checks, 23-11