Configuring Gratuitous Arp - Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual

Configuring Gratuitous ARP

Copyright © 2010, Juniper Networks, Inc.
You can include the
loopback
levels:
[edit interfaces interface-name aggregated-ether-options]
[edit interfaces interface-name ether-options]
[edit interfaces interface-name fastether-options]
[edit interfaces interface-name gigether-options]
Gratuitous Address Resolution Protocol (ARP) requests provide duplicate IP address
detection. A gratuitous ARP request is a broadcast request for a router's own IP address.
If a router or switch sends an ARP request for its own IP address and no ARP replies are
received, the router- or switch-assigned IP address is not being used by other nodes. If a
router or switch sends an ARP request for its own IP address and an ARP reply is received,
the router- or switch-assigned IP address is already being used by another node.
By default, the router or switch responds to gratuitous ARP requests. On Ethernet
interfaces, you can disable responses to gratuitous ARP requests. To disable responses
to gratuitous ARP requests, include the
interfaces interface-name]
[edit interfaces interface-name]
no-gratuitous-arp-request;
To return to the default—that is, to respond to gratuitous ARP requests—delete the
no-gratuitous-arp-request
[edit]
user@host# delete interfaces interface-name no-gratuitous-arp-request
Gratuitous ARP replies are reply packets sent to the broadcast MAC address with the
target IP address set to be the same as the sender's IP address. When the router or switch
receives a gratuitous ARP reply, the router or switch can insert an entry for that reply in
the ARP cache.
By default, updating the ARP cache on gratuitous ARP replies is disabled on the router
or switch. On Ethernet interfaces, you can enable handling of gratuitous ARP replies on
a specific interface by including the
hierarchy level:
interface-name]
[edit interfaces interface-name]
gratuitous-arp-reply;
To restore the default behavior, include the
[edit interfaces interface-name]
[edit interfaces interface-name]
no-gratuitous-arp-reply;
and statements at the following hierarchy
no-loopback
no-gratuitous-arp-request
hierarchy level:
statement from the configuration:
gratuitous-arp-reply
no-gratuitous-arp-reply
hierarchy level:
Chapter 58: Configuring Interfaces
statement at the
statement at the
[edit interfaces
statement at the
[edit
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