Cisco 7604 - Page 590

38-18
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
OL-4266-08
Chapter 38 Configuring Dynamic ARP Inspection
DAI Configuration Samples
Step 5 Check the statistics before and after DAI processes any packets:
RouterA# 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
RouterA#
If Host 1 then sends out two ARP requests with an IP address of 1.1.1.2 and a MAC address of
0002.0002.0002, both requests are permitted, as reflected in the following statistics:
RouterA# show ip arp inspection statistics vlan 1
Vlan Forwarded Dropped DHCP Drops ACL Drops
---- --------- ------- ---------- ----------
1 2 0 0 0
Vlan DHCP Permits ACL Permits Source MAC Failures
---- ------------ ----------- -------------------
1 2 0 0
Vlan Dest MAC Failures IP Validation Failures
---- ----------------- ----------------------
1 0 0
RouterA#
If Host 1 then tries to send an ARP request with an IP address of 1.1.1.3, the packet is dropped and an
error message is logged:
00:12:08: %SW_DAI-4-DHCP_SNOOPING_DENY: 2 Invalid ARPs (Req) on Fa6/4, vlan
1.([0002.0002.0002/1.1.1.3/0000.0000.0000/0.0.0.0/02:42:35 UTC Tue Jul 10 2001])
RouterA# show ip arp inspection statistics vlan 1
RouterA#
The statistics will display as follows:
Vlan Forwarded Dropped DHCP Drops ACL Drops
---- --------- ------- ---------- ----------
1 2 2 2 0
Vlan DHCP Permits ACL Permits Source MAC Failures
---- ------------ ----------- -------------------
1 2 0 0
Vlan Dest MAC Failures IP Validation Failures
---- ----------------- ----------------------
1 0 0
RouterA#