Configuring Arp - 3Com 8807 Configuration Manual

672 C 55: ARP C
HAPTER

Configuring ARP

Manually
Adding/Deleting Static
ARP Mapping Entries
ONFIGURATION
Normally, dynamic ARP takes effect and automatically searches for the resolution
from the IP address to the Ethernet MAC address without the help of an
administrator.
ARP concepts
ARP entries used in Switch 8800 Family series routing switches include dynamic
ARP entries and static ARP entries. Static entries are further divided into long static
ARP entries and short static ARP entries.
Dynamic ARP entries are automatically created and maintained by the ARP
■
protocol through ARP packets. They can be discarded after the aging time
expires, and updated by new ARP packets. They can also be overlaid by long
static ARP entries and short static ARP entries. When the aging time expires,
the port is disabled or the VLAN interface is disabled, dynamic ARP entries will
be deleted.
Static ARP entries are configured and maintained manually, including short ARP
■
entries and long ARP entries.
Long ARP entries contain all elements of an ARP entry. They can forward data
■
directly. They cannot be aged, and overlaid by dynamic ARP entries.
Short ARP entries are configured with IP addresses and MAC addresses only
■
other than VLANs and egresses. They are generally used in users requiring IP
address and MAC address binding. Its initial state is non-resolution, so it cannot
forward data directly. It can resolve VLANs and egresses dynamically through
ARP packets. A resolved static ARP entry can forward data and will not be
aged. When the port and VLAN interface are disabled, a static ARP entry will be
restored to the non-resolution state.
The ARP mapping table can be maintained dynamically or manually. Usually, the
manually configured mapping from the IP addresses to the MAC addresses is
known as static ARP. The user can display, add or delete the entries in the ARP
mapping table through relevant manual maintenance commands.
The following sections describe static ARP configuration tasks:
"Manually Adding/Deleting Static ARP Mapping Entries"
■
"Configuring the Dynamic ARP Aging Timer"
■
"Adding/Deleting Multicast ARP Ports"
■
"ARP Proxy Configuration"
■
"Gratuitous ARP Learning Configuration"
■
"Configuring ARP Packets Not to Broadcast in VLAN"
■
Perform the following configuration in system view.
Table 608 Manually add/delete static ARP mapping entries
Operation
Manually add a static ARP
mapping entry
Manually delete a static ARP
mapping entry
Command
arp static ip-address [ mac-address [ vlan-id { interface-type
interface-number } ] [ vpn-instance vpn-instance-name ] ]
undo arp ip-address