Configuring Security
Dynamic ARP Inspection
Cisco 500 Series Stackable Managed Switch Administration Guide
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Source MAC —
Compares the packet’s source MAC address in the
Ethernet header against the sender’s MAC address in the ARP request. This
check is performed on both ARP requests and responses.
•
Destination MAC —
Compares the packet’s destination MAC address in
the Ethernet header against the destination interface’s MAC address. This
check is performed for ARP responses.
•
IP Addresses —
Compares the ARP body for invalid and unexpected IP
addresses. Addresses include 0.0.0.0, 255.255.255.255, and all IP Multicast
addresses.
Packets with invalid ARP Inspection bindings are logged and dropped.
Up to 1024 entries can be defined in the ARP Access Control table.
Interaction Between ARP Inspection and DHCP Snooping
If DHCP Snooping is enabled, ARP Inspection uses the DHCP Snooping Binding
database in addition to the ARP access control rules. If DHCP Snooping is not
enabled, only the ARP access control rules are used.
ARP Defaults
Figure 11 ARP Defaults
Option
Default State
Dynamic ARP Inspection
Not enabled.
ARP Packet Validation
Not enabled
ARP Inspection Enabled on VLAN
Not enabled
Log Buffer Interval
SYSLOG message generation for dropped
packets is enabled at 5 seconds interval