20-8
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
78-13315-02
Chapter 20 Administering the Switch
Configuring Permanent and Static ARP Entries
The primary gateway: 172.20.52.121
Destination Gateway RouteMask Flags Use Interface
--------------- --------------- ---------- ----- -------- ---------
172.16.16.0 172.20.52.127 0xfffff000 UG 0 sc0
default 172.20.52.121 0x0 UG 0 sc0
172.20.52.120 172.20.52.124 0xfffffff8 U 1 sc0
default default 0xff000000 UH 0 sl0
Console> (enable)
C
onfiguring Permanent and Static ARP Entries
To enable your Catalyst LAN switch to communicate with devices that do not respond to Address
Resolution Protocol (ARP) requests, you can configure a static or permanent ARP entry that maps the
IP addresses of those devices to their MAC addresses. You can configure an ARP entry so that it does
not age out by configuring it as either static or permanent. When you configure a static ARP entry using
the
set arp static
command, the entry is removed from the ARP cache after a system reset. When you
configure a permanent ARP by using the
set arp permanent
command, the ARP entry is retained even
after a system reset.
Because most hosts support dynamic resolution, you usually do not need to specify static or permanent
ARP cache entries. When a device does not respond to ARP requests, you can configure an ARP entry
to be statically or permanently entered into the ARP cache so that those devices can still be reached.
To configure a static or permanent ARP entry, perform this task in privileged mode:
This example shows how to define a static ARP entry:
Console> (enable)
set arp static 20.1.1.1 00-80-1c-93-80-40
Static ARP entry added as
20.1.1.1 at 00-80-1c-93-80-40 on vlan 1
Console> (enable)
This example shows how to define a permanent ARP entry:
Console> (enable)
set arp permanent 10.1.1.1 00-80-1c-93-80-60
Permanent ARP entry added as
10.1.1.1 at 00-80-1c-93-80-60 on vlan 1
Console> (enable)
This example shows how to set the ARP aging time:
Console> (enable)
set arp agingtime 300
ARP aging time set to 300 seconds.
Console> (enable)
Task
Command
Step 1
Configure a static or permanent ARP entry.
set arp
[
dynamic
|
permanent
|
static
] {
ip_addr
hw_addr
}
Step 2
(Optional) Specify the ARP aging time.
set arp agingtime
seconds
Step 3
Verify the ARP configuration.
show arp