Configuring Gratuitous Arp - Juniper EX2200 Hardware Manual

Network Interfaces for EX4300 Switches

Configuring Gratuitous ARP

Related
Documentation
78
EX Series Switches Interfaces Overview on page 3
Ethernet Interfaces
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;
gratuitous-arp-reply on page 182
no-gratuitous-arp-request on page 214
Ethernet Interfaces Overview
EX Series Switches Interfaces Overview on page 3
Ethernet Interfaces
no-gratuitous-arp-request
hierarchy level:
statement from the configuration:
gratuitous-arp-reply
no-gratuitous-arp-reply
hierarchy level:
statement at the
statement at the [edit interfaces
statement at the
Copyright © 2015, Juniper Networks, Inc.
[edit