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Software Configuration Guide—Release 15.0(2)SG
OL-23818-01
Chapter 46 Configuring Dynamic ARP Inspection
Configuring Dynamic ARP Inspection
Step 5 Switch(config)# ip arp inspection filter arp-acl-name
vlan vlan-range [static]Applies the ARP ACL to the VLAN. By default, no
defined ARP ACLs are applied to any VLAN.
For arp-acl-name, specify the name of the ACL
created in Step 2.
For vlan-range, specify the VLAN that the
switches and hosts are in. You can specify a
single VLAN identified by VLAN ID number, a
range of VLANs separated by a hyphen, or a
series of VLANs separated by a comma. The
range is 1 to 4094.
(Optional) Specify static to treat implicit denies
in the ARP ACL as explicit denies and to drop
packets that do not match any previous clauses in
the ACL. DHCP bindings are not used.
If you do not specify this keyword, it means that
there is no explicit deny in the ACL that denies
the packet, and DHCP bindings determine
whether a packet is permitted or denied if the
packet does not match any clauses in the ACL.
ARP packets containing only IP-to-MAC address
bindings are compared against the ACL. Packets are
permitted only if the access list permits them.
Step 6 Switch(config)# interface interface-id Specifies the Switch A interface that is connected to
Switch B, and enter interface configuration mode.
Step 7 Switch(config-if)# no ip arp inspection trust Configures the Switch A interface that is connected to
Switch B as untrusted.
By default, all interfaces are untrusted.
For untrusted interfaces, the switch intercepts all
ARP requests and responses. It verifies that the
intercepted packets have valid IP-to-MAC address
bindings before updating the local cache and before
forwarding the packet to the appropriate destination.
The switch drops invalid packets and logs them in the
log buffer according to the logging configuration
specified with the ip arp inspection vlan logging
global configuration command. For more
information, see the “Configuring the Log Buffer”
section on page 46-14.
Step 8 Switch(config-if)# end Returns to privileged EXEC mode.
Step 9 Switch# show arp access-list [acl-name]
Switch# show ip arp inspection vlan vlan-range
Switch# show ip arp inspection interfaces
Verifies the DAI configuration.
Step 10 Switch# copy running-config startup-config (Optional) Saves your entries in the configuration
file.
Command Purpose