Deployment Guide

Table Of Contents
are for DAI; to enable DAI on 16 VLANs, seven more entries are required. 87 L2Protocol + 13 additional L2Protocol + 15
L2SystemFlow + 7 additional L2SystemFlow equals 122.
Configuring Dynamic ARP Inspection
To enable dynamic ARP inspection, use the following commands.
1. Enable DHCP snooping.
2. Validate ARP frames against the DHCP snooping binding table.
INTERFACE VLAN mode
arp inspection
To view entries in the ARP database, use the show arp inspection database command.
Dell#show arp inspection database
Protocol Address Age(min) Hardware Address Interface VLAN CPU
---------------------------------------------------------------------
Internet 10.1.1.251 - 00:00:4d:57:f2:50 Te 0/2 Vl 10 CP
Internet 10.1.1.252 - 00:00:4d:57:e6:f6 Te 0/1 Vl 10 CP
Internet 10.1.1.253 - 00:00:4d:57:f8:e8 Te 0/3 Vl 10 CP
Internet 10.1.1.254 - 00:00:4d:69:e8:f2 Te 0/50 Vl 10 CP
Dell#
To see how many valid and invalid ARP packets have been processed, use the show arp inspection statistics
command.
Dell#show arp inspection statistics
Dynamic ARP Inspection (DAI) Statistics
---------------------------------------
Valid ARP Requests : 0
Valid ARP Replies : 1000
Invalid ARP Requests : 1000
Invalid ARP Replies : 0
Dell#
Bypassing the ARP Inspection
You can configure a port to skip ARP inspection by defining the interface as trusted, which is useful in multi-switch
environments.
ARPs received on trusted ports bypass validation against the binding table. All ports are untrusted by default.
To bypass the ARP inspection, use the following command.
Specify an interface as trusted so that ARPs are not validated against the binding table.
INTERFACE mode
arp inspection-trust
DAI is supported on Layer 2 and Layer 3.
Source Address Validation
Using the DHCP binding table, Dell Networking OS can perform three types of source address validation (SAV).
Table 27. Three Types of Source Address Validation
Source Address Validation Description
IP Source Address Validation Prevents IP spoofing by forwarding only IP packets that have
been validated against the DHCP binding table.
Dynamic Host Configuration Protocol (DHCP) 339