Configuring ARP

The switch maintains an ARP (Address Resolution Protocol) table for all known devices that reside in its directly-connected IP subnets. A directly-connected IP subnet is the subnet to which a IPv4 interface of the switch is connected. When the switch needs 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 switch creates dynamic addresses from the ARP packets it receives. Dynamic addresses age out after a configured time.

NOTE     The IP/MAC address mapping information in the ARP Table is used by the switch to forward traffic originated by the switch.

To define the ARP tables:

  1. Click IP Configuration > ARP (Layer 2) . The ARP Table page opens.
  2. Enter the parameters.
    • 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.
  3. Click Apply. The ARP global settings are modified, and the Running Configuration file is updated.
  4. 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.
    • Status--Whether the entry was manually entered or dynamically learned.
  5. Click Add. The Add ARP Entry page opens.
  6. Enter the parameters:
    • IP Version--The IP address format supported by the host. Only IPv4 is supported.
    • Interface--IPv4 interface on the switch.
    • There is only one directly-connected IP subnet, which is always in the management VLAN. All the static and dynamic addresses in the ARP Table reside in the management VLAN.

  7. IP Address--Enter the IP address of the local device.
  8. MAC Address--Enter the MAC address of the local device.
  9. Click Apply. The ARP entry is defined, and the Running Configuration file is updated.