User's Manual

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The static ARP cache item is generally not required because most hosts support dynamic address resolution.
You can define it in global configuration mode if necessary. The system utilizes the static ARP cache item to
translate the 32-bit IP address into a 48-bit MAC address. Additionally, you can specify the routing SWITCH to
respond to the ARP request for other hosts.
You can set the active period for the ARP entries if you do not want the ARP entry to exist permanently. The
following two types show how to configure the mapping between the static IP address and the MAC address.
Run one of the following commands in global configuration mode:
Command Purpose
arp ip-address hardware-address vlan vlan-id
Globally maps an IP address to a MAC address
in the ARP cache.
arp ip-address hardware-address vlan vlan-id
alias
Specifies the routing SWITCH to respond to the
ARP request of the designated IP address
through the MAC address of the routing
SWITCH.
Run the following command in VLAN interface configuration mode:
Command Purpose
arp timeout seconds
Sets the timeout time of the ARP cache item in
the ARP cache.
arp dynamic
Enables arp dynamic learning in the interface
Run show interfaces to display the ARP timeout time of the designated interface. Run the show arp to check
the content of the ARP cache. Run clear arp-cache to delete all entries in the ARP cache.
Activating proxy ARP
The system uses the proxy ARP (defined by RFC 1027) to obtain the host’s MAC address on other networks
for the hosts without corresponding routes. For example, when the routing SWITCH receives an ARP request
and finds that the source host and the destination host are not connected to the same interface and all the
routes that the routing SWITCH reaches the destination host are not through the interface that receives the
ARP request, it will send a proxy ARP response that contains its address of the link layer. The source host
then sends the message to the routing SWITCH and the SWITCH forwards it to the destination host. The proxy
ARP is activates by default.
To activate the proxy ARP, run the following command in interface configuration mode:
Command Purpose