Junos® OS Ethernet Interfaces Configuration ... - Juniper Networks

CHAPTER 10
Configuring Restricted and Unrestricted
Proxy ARP
• Restricted and Unrestricted Proxy ARP Overview on page 169
• Configuring Restricted and Unrestricted Proxy ARP on page 171
Restricted and Unrestricted Proxy ARP Overview
Restricted Proxy ARP
Unrestricted Proxy ARP
By default, the Junos OS responds to an Address Resolution Protocol (ARP) request only
if the destination address of the ARP request is local to the incoming interface.
For Ethernet Interfaces, you can configure the router or switches to proxy-reply to the
ARP requests using the restricted or unrestricted proxy ARP configuration.
You might want to configure restricted or unrestricted proxy ARP for routers that act as
provider edge (PE) devices in Ethernet Layer 2 LAN switching domains.
NOTE: From Junos OS Release 10.0 onward, Junos OS does not respond to
proxy ARP requests with the default route 0.0.0.0. This behavior is in
compliance with RFC 1027.
Restricted proxy ARP enables the router or switch to respond to the ARP requests in
which the physical networks of the source and target are not the same and the router or
switch has an active route to the target address in the ARP request. The router does not
reply if the target address is on the same subnet and the same interface as the ARP
requestor.
Unrestricted proxy ARP enables the router or switch to respond to any ARP request, on
condition that the router has an active route to the destination address of the ARP request.
The route is not limited to the incoming interface of the request, nor is it required to be a
direct route.
Copyright © 2012, Juniper Networks, Inc.
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