SMAC Fails-ARP Req = 0
SMAC Fails-ARP Res = 0
DMAC Fails-ARP Res = 0
IP Fails-ARP Req
= 0
IP Fails-ARP Res
= 0
If host 1 tries to send an ARP request with an IP address of 10.0.0.3, the packet is dropped, and an error message is logged.
00:12:08: %SW_DAI-4-DHCP_SNOOPING_DENY: 2 Invalid ARPs (Req) on Ethernet2/3, vlan
1.([0002.0002.0002/10.0.0.3/0000.0000.0000/0.0.0.0/02:42:35 UTC Fri Jan 23 2015])
The statistics display as follows:
switchA#
show ip arp inspection statistics vlan 1
switchA#
Vlan : 1
-----------
ARP Req Forwarded
= 2
ARP Res Forwarded
= 0
ARP Req Dropped
= 2
ARP Res Dropped
= 0
DHCP Drops
= 2
DHCP Permits
= 2
SMAC Fails-ARP Req = 0
SMAC Fails-ARP Res = 0
DMAC Fails-ARP Res = 0
IP Fails-ARP Req
= 0
IP Fails-ARP Res
= 0
switchA#
Configuring Device B
To enable DAI and configure Ethernet interface 1/4 on device B as trusted, follow these steps:
Step 1
While logged into device B, verify the connection between device B and device A.
switchB#
show cdp neighbors
Capability Codes: R - Router, T - Trans-Bridge, B - Source-Route-Bridge
S - Switch, H - Host, I - IGMP, r - Repeater,
V - VoIP-Phone, D - Remotely-Managed-Device,
s - Supports-STP-Dispute
Device ID
Local Intrfce
Hldtme
Capability
Platform
Port ID
switchA
Ethernet1/4
120
R S I
WS-C2960-24TC Ethernet2/3
switchB#
Step 2
Enable DAI on VLAN 1 and verify the configuration.
switchB#
configure terminal
switchB(config)#
ip arp inspection vlan 1
switchB(config)#
show ip arp inspection vlan 1
Source Mac Validation
: Disabled
Destination Mac Validation : Disabled
IP Address Validation
: Disabled
Vlan : 1
-----------
Configuration
: Enabled
Operation State : Active
Cisco Nexus 9000 Series NX-OS Security Configuration Guide, Release 9.x
402
Configuring Dynamic ARP Inspection
Configuring Device B