Configuring Permanent And Static Arp Entries On The Switch - Cisco WS-C6506 Software Manual

Chapter 22 Administering the Switch

Configuring Permanent and Static ARP Entries on the Switch

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:
Task
Step 1 Configure a static or permanent ARP entry.
Step 2 (Optional) Specify the ARP aging time.
Step 3 Verify the ARP configuration.
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)
This example shows how to display the ARP cache:
Console> (enable) show arp
ARP Aging time = 300 sec
+ - Permanent Arp Entries
* - Static Arp Entries
+ 10.1.1.1 at 00-80-1c-93-80-60 on vlan 1
172.20.52.1 at 00-60-5c-86-5b-28 port
* 20.1.1.1 at 00-80-1c-93-80-40 port
Console> (enable)
OL-8978-04
Configuring Permanent and Static ARP Entries on the Switch
Command
set arp [dynamic | permanent | static] {ip_addr
hw_addr}
set arp agingtime seconds
show arp
8/1 on vlan 1
8/1 on vlan 1
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
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