Administering The Arp Cache - 3Com SuperStack II 3300 User Manual

70 C 8: S
HAPTER ETTING
Administering the
ARP Cache
Displaying the ARP
Cache
Defining a Static ARP
Cache Entry
IP P
ARAMETERS
The Layer 3 Module uses the Address Resolution Protocol (ARP) to find
the MAC addresses corresponding to the IP addresses of hosts and other
routers on the same subnets. Each device participating in routing
maintains an ARP cache — a table of known IP addresses and their
corresponding MAC addresses.
ARP usually learns the MAC and IP addresses of devices. Static entries are
useful to make sure that key hosts, for example, other routers, can be
contacted immediately after a restart.
Enter the following at the top-level menu:
ip arp display
The following example shows an IP ARP cache display:
ARP usually learns the MAC to IP address mapping of devices dynamically.
Static entries are useful to ensure that key hosts, for example, other
routers, can be contacted immediately after the Layer 3 Module is
restarted.
To define a static ARP cache entry:
1 Enter the following at the top-level menu:
ip arp static
The following prompt is displayed:
Select interface index {1-2}:
2 Select the IP interface index.
Enter IP address:
3 Enter the IP address of the ARP cache entry.
Enter MAC address:
4 Enter the MAC address of the ARP cache entry.