Configuring Proxy ND

A device can function as the proxy of a target host to reply to unreachable requests in special scenarios.

Usage Scenarios

ND applies only to the communication of hosts on the same network segment and physical network. When a router receives an NS packet from a host, the router checks whether the destination IPv6 address in the NS packet is the local IPv6 address. This helps to determine whether the NS packet requests for the local MAC address. If yes, an NA packet is sent as a reply. If not, the NS packet is discarded.

For the hosts on the same network segment but different physical networks or the hosts that are on the same network segment and physical network but fail in Layer 2 interworking, proxy ND can be deployed on the router between the hosts to allow such hosts to communicate with each other. After proxy ND is deployed and the router receives an NS packet, the router finds that the destination address in the NS packet is not its own IPv6 address and then replies the source host with an NA packet carrying its own MAC address and the IPv6 address of the destination host. Specifically, the router takes the place of the destination host to reply with an NA packet.

Table 1 describes the usage scenarios for different types of proxy ND.

**Table 1** Usage scenarios of proxy ND
Proxy ND Mode	Usage Scenario
Routed proxy ND	Hosts that need to communicate reside on the same network segment but different physical networks, and the gateways connecting to the two hosts are configured with different IP addresses.
Any proxy ND	Hosts that need to communicate reside on the same network segment but different physical networks, and the gateways connected to the hosts have the same gateway address.
Intra-VLAN proxy ND	Hosts that need to communicate reside on the same network segment and belong to the same VLAN, but user isolation is configured in the VLAN.
Inter-VLAN proxy ND	Hosts that need to communicate reside on the same network segment but belong to different VLANs.
Local proxy ND	Hosts that need to communicate reside on the same network segment and BD, but user isolation is configured in the BD.

Pre-configuration Tasks

Before configuring proxy ND, complete the following tasks:

Connect interfaces and set their physical parameters to ensure that the physical interface status is Up.
Configure the link layer protocol parameters for interfaces.
Enable IPv6 in the interface view.
Configure IPv6 addresses for interfaces.

Configuring Routed Proxy ND: Routed proxy ND can be deployed if two hosts are on the same network segment but different physical networks and the gateway connecting to the two hosts are configured with two different IP addresses.

Configuring Any Proxy ND: Any proxy ND can be deployed if two hosts are on the same network segment but different physical networks and the gateways connecting to the two hosts have the same IP address.

Configuring Intra-VLAN Proxy ND: Intra-VLAN proxy ND can be deployed if two hosts are on the same VLAN but the VLAN is configured with Layer 2 port isolation.

Configuring Inter-VLAN Proxy ND: Inter-VLAN proxy ND can be deployed if two hosts that are on the same network segment and physical network but belong to different VLANs need to communicate with each other at Layer 3.

Configuring Local Proxy ND: Local proxy ND can be deployed if two hosts on the same network segment and in the same BD want to communicate with each other but the BD is configured with split horizon.