Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual page 3230

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OS for EX Series Ethernet Switches, Release 10.4
This example shows the configuration of proxy ARP on an interface of an EX Series switch
using restricted mode. In restricted mode, the switch does not proxy for hosts on the
same subnet.
The topology for this example consists of one EX Series switch. When a host wants to
communicate with a host that is not already in its ARP table, it broadcasts an ARP request
for the MAC address of the destination host:
When proxy ARP is not enabled, a host that shares the same IP address replies directly
to the ARP request, providing its MAC address, and future transmissions are sent directly
to the destination host MAC address.
When proxy ARP is enabled, the switch responds to ARP requests, providing the switch's
MAC address—even when the destination IP address is the same as the source IP
address. Thus, communications must be sent through the switch and then routed
through the switch to the appropriate destination.
To configure proxy ARP, perform the following tasks:
To quickly configure proxy ARP on an interface, copy the following command and paste
it into the switch terminal window:
[edit]
set interfaces ge-0/0/3 unit 0 proxy-arp restricted
You configure proxy ARP on individual interfaces.
To configure proxy ARP on an interface:
1.
[edit interfaces]
user@switch# set ge-0/0/3 unit 0 proxy-arp restricted
BEST PRACTICE: We recommend that you configure proxy ARP in
restricted mode. In restricted mode, the switch does not act as proxy if
the source and target IP addresses are on the same subnet. If you use
unrestricted mode, disable gratuitous ARP requests on the interface to
avoid the situation of the switch's response to a gratuitous ARP request
appearing to the host to be an indication of an IP conflict:
[edit interfaces]
user@switch# set ge-0/0/3 no-gratuitous-arp-request
Display the results of the configuration:
user@switch> show configuration
interfaces {
ge-0/0/3 {
unit 0 {
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