Cisco 7604

38-20
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
OL-4266-08
Chapter 38 Configuring Dynamic ARP Inspection
DAI Configuration Samples
------------------ --------------- ---------- ------------- ---- --------------------
00:01:00:01:00:01 1.1.1.1 4995 dhcp-snooping 1 FastEthernet3/4
RouterB#
Step 5 Check the statistics before and after DAI processes any packets:
RouterB# show ip arp inspection statistics vlan 1
Vlan Forwarded Dropped DHCP Drops ACL Drops
---- --------- ------- ---------- ----------
1 0 0 0 0
Vlan DHCP Permits ACL Permits Source MAC Failures
---- ------------ ----------- -------------------
1 0 0 0
Vlan Dest MAC Failures IP Validation Failures
---- ----------------- ----------------------
1 0 0
RouterB#
If Host 2 then sends out an ARP request with the IP address 1.1.1.1 and the MAC address
0001.0001.0001, the packet is forwarded and the statistics are updated appropriately:
RouterB# show ip arp inspection statistics vlan 1
Vlan Forwarded Dropped DHCP Drops ACL Drops
---- --------- ------- ---------- ----------
1 1 0 0 0
Vlan DHCP Permits ACL Permits Source MAC Failures
---- ------------ ----------- -------------------
1 1 0 0
Vlan Dest MAC Failures IP Validation Failures
---- ----------------- ----------------------
1 0 0
RouterB#
If Host 2 attempts to send an ARP request with the IP address 1.1.1.2, DAI drops the request and logs a
system message:
00:18:08: %SW_DAI-4-DHCP_SNOOPING_DENY: 1 Invalid ARPs (Req) on Fa3/4, vlan
1.([0001.0001.0001/1.1.1.2/0000.0000.0000/0.0.0.0/01:53:21 UTC Fri May 23 2003])
RouterB#
The statistics display as follows:
RouterB# show ip arp inspection statistics vlan 1
Vlan Forwarded Dropped DHCP Drops ACL Drops
---- --------- ------- ---------- ----------
1 1 1 1 0
Vlan DHCP Permits ACL Permits Source MAC Failures
---- ------------ ----------- -------------------
1 1 0 0
Vlan Dest MAC Failures IP Validation Failures
---- ----------------- ----------------------
1 0 0
RouterB#