Configuring Arp Fast-Reply; Overview; Configuration Procedure; Arp Fast-Reply Configuration Example - HPE FlexNetwork MSR Series Comware 7 Layer 3 - Ip Services Configuration Manuals

Configuring ARP fast-reply

Overview

ARP fast-reply enables a device to directly answer ARP requests according to DHCP snooping
entries or ARP snooping entries. ARP fast-reply functions in a VLAN. For information about DHCP
snooping, see "Configuring DHCP snooping."
If the target IP address of a received ARP request is the IP address of the VLAN interface, the device
delivers the request to the ARP module. If not, the device takes the following steps to process the
packet:
1. Search the DHCP snooping table for a match by using the target IP address.
2. If a match is found, whether the device returns a reply depends on the type of interface in the
matching entry.
If the interface is the Ethernet interface that received the ARP request, the device does not
return any reply.
If the interface is a wireless interface or an Ethernet interface other than the receiving
interface, the device returns a reply according to the matching entry.
3. If no matching DHCP snooping entry is found and ARP snooping is enabled, the device
searches the ARP snooping table.
If the interface in the matching entry is the Ethernet interface that received the ARP request,
the device does not return any reply.
If the interface is a wireless interface or an Ethernet interface other than the receiving
interface, the device returns a reply according to the ARP snooping entry.
4. If no match is found in both tables, the ARP request is forwarded to other interfaces except the
receiving interface in the VLAN, or delivered to other modules.

Configuration procedure

To improve the availability of ARP fast-reply, enable ARP snooping at the same time.
To configure ARP fast-reply:
Step
1. Enter system view.
2. Enter VLAN view.
3. Enable ARP fast-reply.

ARP fast-reply configuration example

Network requirements

As shown in
have obtained IP addresses through DHCP.
Enable ARP snooping and ARP fast-reply for VLAN 2. The router directly returns an ARP reply
without broadcasting received ARP requests in the VLAN.
Command
system-view
vlan vlan-id
arp fast-reply enable
Figure 6, all clients are in VLAN 2, and access the network through the router. They
Remarks
N/A
N/A
By default, ARP fast-reply is disabled.
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