3com S7906E Manuel De Montage

 

2-2 

You can solve the problem by enabling proxy ARP on Switch. After that, Switch can reply to the ARP 

request from Host A with the MAC address of Vlan-interface1, and forward packets sent from Host A to 

Host B. In this case, Switch seems like a proxy of Host B. 

A main advantage of proxy ARP is that it is added on a single Switch without disturbing routing tables of 

other Switchs in the network. Proxy ARP acts as the gateway for IP hosts that are not configured with a 

default gateway or do not have routing capability. 

As shown in 

, Host A and Host B belong to VLAN 2, but are isolated at Layer 2. Host A 

connects to GigabitEthernet2/0/3 while Host B connects to GigabitEthernet2/0/1. Enable local proxy 

ARP on Switch A to allow Layer 3 communication between the two hosts. 

Figure 2-2 Application environment of local proxy ARP 

 

 

 

In one of the following cases, you need to enable local proxy ARP: 

z 

Hosts connecting to different isolated Layer 2 ports in the same VLAN need to communicate at 

Layer 3. 

z 

If a super VLAN is configured, hosts in different sub VLANs of the super VLAN need to 

communicate at Layer 3. 

z 

If an isolate-user-VLAN is configured, hosts in different secondary VLANs of the 

isolate-user-VLAN need to communicate at Layer 3. 

Follow these steps to enable proxy ARP in VLAN interface view: 

Enter system view 

system-view 

— 

Enter interface view 

interface interface-type 
interface-number 

Required 

Enable proxy ARP 

proxy-arp enable 

Required 

Disabled by default. 

 

Follow these steps to enable local proxy ARP in VLAN interface view: