IP Configuration
IPv4 Management and Interfaces
261 Cisco Small Business 300 Series Managed Switch Administration Guide
16
ARP
The device maintains an ARP (Address Resolution Protocol) table for all known
devices that reside in the IP subnets directly connected to it. A directly-connected
IP subnet is the subnet to which an IPv4 interface of the device is connected.
When the device is required to send/route a packet to a local device, it searches
the ARP table to obtain the MAC address of the device. The ARP table contains
both static and dynamic addresses. Static addresses are manually configured and
do not age out. The device creates dynamic addresses from the ARP packets it
receives. Dynamic addresses age out after a configured time.
NOTE In Layer 2 mode, the IP, MAC address mapping in ARP Table is used by the device
to forward traffic originated by the device. In Layer3 mode, the mapping
information is used for Layer3 routing as well as to forward generated traffic.
To define the ARP tables:
STEP 1 Click IP Configuration > IPv4 Management and Interfaces > ARP.
STEP 2 Enter the pa rameters.
•ARP Entry Age Out—Enter the number of seconds that dynamic addresses
can remain in the ARP table. A dynamic address ages out after the time it is
in the table exceeds the ARP Entry Age Out time. When a dynamic address
ages out, it is deleted from the table, and only returns when it is relearned.
•Clear ARP Table Entries—Select the type of ARP entries to be cleared from
the system.
-

All

—Deletes all of the static and dynamic addresses immediately.
-
Dynamic
—Deletes all of the dynamic addresses immediately.
-
Static
—Deletes all of the static addresses immediately.
-

Normal Age Out

—Deletes dynamic addresses based on the configured
ARP Entry Age Out time.
STEP 3 Click Apply. The ARP global settings are written to the Running Configuration file.
The ARP table displays the following fields:
•Interface—The IPv4 Interface of the directly-connected IP subnet where the
IP device resides.
•IP Address—The IP address of the IP device.
•MAC Address—The MAC address of the IP device.