Defining And Using Ip Aliases; Configuring Permanent And Static Arp Entries - Cisco WS-C4003 - Catalyst 4000 Chassis Switch Software Configuration Manual

Chapter 26 Administering the Switch

Defining and Using IP Aliases

You can use the set ip alias command to define aliases for IP addresses. IP aliases can make it easier to
refer to other network devices when you use ping, telnet, and other commands, even when (DNS) is not
enabled.
For the name argument, specify a name for your IP alias. For the ip_addr argument, specify the IP
address to which the name refers.
To define an IP alias on the switch, perform this task in privileged mode:
Task
Step 1
Define an IP alias on the switch.
Step 2
Verify the currently defined IP aliases.
This example shows how to define two IP aliases, sparc, which refers to IP address 172.20.52.3, and
cat4003, which refers to IP address 172.20.52.71. This example also shows how to verify the currently
defined IP aliases:
Console> (enable) set ip alias sparc 172.20.52.3
IP alias added.
Console> (enable) set ip alias cat4003 172.20.52.71
IP alias added.
This example show what happens when you use the IP aliases with the ping command.
Console> (enable) show ip alias
default
sparc
cat5509
Console> (enable) ping sparc
sparc is alive
Console> (enable) ping cat4003
cat4003 is alive
Console> (enable)

Configuring 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.
78-12647-02
0.0.0.0
172.20.52.3
172.20.52.71
Software Configuration Guide—Catalyst 4000 Family, Catalyst 2948G, Catalyst 2980G, Releases 6.3 and 6.4
Defining and Using IP Aliases
Command
set ip alias name ip_addr
show ip alias [name]
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