584 CHAPTER 55: P ROXY ARP C ONFIGURATIONVLAN-interface 3 of the switch, and then the switch routes the packets to HostD, so as to realize the Layer 3 connectivity between Host A and Host D.Proxy ARP is needed in the following cases (hosts have IP addresses of the samenetwork segment).■ For hosts in different VLANs on a Switch 7750 to communicate, you need toenable proxy ARP on the VLAN interfaces.■ For hosts in different sub-VLANs of a super VLAN on a Switch 7750 tocommunicate, you need to enable proxy ARP on the super VLAN interface.■ For hosts in different secondary VLANs of an isolate-user-vlan on a Layer 2switch that is connected to a Switch 7750 to communicate, you need to enableproxy ARP on the Switch 7750.n ■ Generally, ports in the same VLAN are interconnected at Layer 2 by default. So,ARP proxy only processes inter-VLAN ARP requests and does not deal withintra-VLAN ARP requests.■ When isolate-user-vlan function is enabled on the Layer 2 switches connectedwith the Switch 7750, ports in the same VLAN are isolated with each other atLayer 2. To provide Layer 3 connectivity between Layer 2 isolated ports in thesame VLAN, you need to enable the intra-VLAN ARP proxy function on theSwitch 7750 to have ARP proxy process intra-VLAN ARP requests.Configuring Proxy ARPProxy ARPConfigurationExampleProxy ARP ConfigurationExampleNetwork requirements■ The IP address of PC A is 192.168.0.22/16, and that of PC D is192.168.1.30/16.■ Create VLAN 3 and VLAN 4 on the switch.Table 460 Configure proxy ARPOperation Command DescriptionEnter system view system-view -Enter VLAN interfaceviewinterface Vlan-interfacevlan-id-Enable proxy ARP arp proxy enable RequiredBy default, proxy ARP is disabled.Enable intra-VLANproxy ARParp proxy source-vlanenableOptionalBy default, intra-VLAN proxy ARP isdisabled, and the proxy ARP onlyprocesses inter-VLAN ARP requests.Display the status ofARP proxydisplay arp proxy[ interface interface-typeinterface-number ]Available in any view
