Chapter 2
Configuring IPv4
S e n d d o c u m e n t c o m m e n t s t o n e x u s 3 k - d o c f e e d b a c k @ c i s c o . c o m
DETAILED STEPS
Command
Step 1
configure terminal
Example:
switch# configure terminal
switch(config)#
Step 2
interface ethernet number
Example:
switch(config)# interface ethernet 2/3
switch(config-if)#
Step 3
no switchport
Example:
switch(config-if)# no switchport
Step 4
ip arp gratuitous {request | update}
Example:
switch(config-if)# ip arp gratuitous
request
Step 5
copy running-config startup-config
Example:
switch(config-if)# copy running-config
startup-config
This example shows how to disable gratuitous ARP requests:
switch# configure terminal
switch(config)# interface ethernet 2/3
switch(config-if)# no switchport
switch(config-if)# no ip arp gratuitous request
switch(config-if)# copy running-config startup-config
Configuring IP Directed Broadcasts
An IP directed broadcast is an IP packet whose destination address is a valid broadcast address for some
IP subnet, but which originates from a node that is not itself part of that destination subnet.
A switch that is not directly connected to its destination subnet forwards an IP directed broadcast in the
same way it would forward unicast IP packets destined to a host on that subnet. When a directed
broadcast packet reaches a switch that is directly connected to its destination subnet, that packet is
"exploded" as a broadcast on the destination subnet. The destination address in the IP header of the
packet is rewritten to the configured IP broadcast address for the subnet, and the packet is sent as a
link-layer broadcast.
If directed broadcast is enabled for an interface, incoming IP packets whose addresses identify them as
directed broadcasts intended for the subnet to which that interface is attached will be exploded as
broadcasts on that subnet.
Cisco Nexus 3000 Series NX-OS Unicast Routing Configuration Guide, NX-OS Release 5.0(3)U1(1)
Purpose
Enters configuration mode.
Enters interface configuration mode.
Configures the interface as a Layer 3 routed interface.
Enables gratuitous ARP on the interface. Default is
enabled.
(Optional) Saves this configuration change.
Configuring IPv4
2-13