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Cisco IE 3000 Switch Software Configuration Guide
OL-13018-03
Chapter 24 Configuring Dynamic ARP Inspection
Configuring Dynamic ARP Inspection
To disable dynamic ARP inspection, use the
no ip arp inspection vlan
vlan-range
global configuration
command. To return the interfaces to an untrusted state, use the
no ip arp inspection trust
interface
configuration command.
This example shows how to configure dynamic ARP inspection on Switch A in VLAN 1. You would
perform a similar procedure on Switch B:
Switch(config)#
ip arp inspection vlan 1
Switch(config)#
interface gigabitethernet0/1
Switch(config-if)#
ip arp inspection trust
Configuring ARP ACLs for Non-DHCP Environments
This procedure shows how to configure dynamic ARP inspection when Switch B shown in
Figure 24-2
on page 24-3
does not support dynamic ARP inspection or DHCP snooping.
If you configure port 1 on Switch A as trusted, a security hole is created because both Switch A and
Host 1 could be attacked by either Switch B or Host 2. To prevent this possibility, you must configure
port 1 on Switch A as untrusted. To permit ARP packets from Host 2, you must set up an ARP ACL and
apply it to VLAN 1. If the IP address of Host 2 is not static (it is impossible to apply the ACL
configuration on Switch A) you must separate Switch A from Switch B at Layer 3 and use a router to
route packets between them.
Beginning in privileged EXEC mode, follow these steps to configure an ARP ACL on Switch A. This
procedure is required in non-DHCP environments.
Step 7
show ip arp inspection interfaces
show ip arp inspection vlan
vlan-range
Verify the dynamic ARP inspection configuration.
Step 8
show ip dhcp snooping binding
Verify the DHCP bindings.
Step 9
show ip arp inspection statistics vlan
vlan-range
Check the dynamic ARP inspection statistics.
Step 10
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Command
Purpose
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
arp access-list
acl-name
Define an ARP ACL, and enter ARP access-list
configuration mode. By default, no ARP access lists
are defined.
Note
At the end of the ARP access list, there is an
implicit
deny ip any mac any
command.
Содержание IE 3000
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