H3C Technologies H3C SecBlade NetStream Cards - Manual (Page 137)

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Proxy ARP configuration
This chapter includes these sections:
• Proxy ARP overview
• Enabling proxy ARP
• Displaying and maintaining proxy ARP
• Proxy ARP configuration examples
Proxy ARP overview
Proxy ARP includes common proxy ARP and local proxy ARP.
• Common proxy ARP allows communication when a sending host considers the receiving host to be
on the same subnet, but the receiving host actually resides on a different subnet.
• Local proxy ARP allows communication between hosts that reside on the same subnet but are
isolated at Layer 2.
In both cases, a device located between the two hosts must respond to the request with the MAC address
of the receiving interface to allow Layer 3 communication between the two hosts. This is achieved by
proxy ARP, which hides the physical details of the network.
NOTE:
The term proxy ARP in the following sections of this chapter refers to common proxy ARP unless otherwise
specified.
Proxy ARP
A proxy ARP enabled device allows hosts that reside on different subnets to communicate.
As shown in
Figure 40 , the SecBlade connects to two subnets through GigabitEthernet 0/2 and
GigabitEthernet 0/3. The IP addresses of the two interfaces are 192.168.10.99/24 and
192.168.20.99/24. Host A and Host B are assigned the same prefix 192.168.0.0. Host A connects to
GigabitEthernet 0/2 and Host B connects to GigabitEthernet 0/3.