Overview of ND Snooping

Definition

Neighbor discovery (ND) snooping is a security feature of IPv6 ND and applies to Layer 2 networks. After ND snooping is enabled on a device, the device listens on neighbor solicitation (NS) packets in the duplicate address detection (DAD) process to establish a dynamic ND snooping binding table. The table records source IPv6 addresses, MAC addresses, VLANs, and inbound ports of NS packets to defend against ND attacks from bogus hosts or gateways.

For details about ND, see Neighbor Discovery in "Basic IPv6 Configurations" in the S2720, S5700, and S6700 V200R019C10 Configuration Guide - IP Service.

Purpose

ND provides powerful functions but has no security mechanism. Attackers often use ND to attack network devices. ND attacks include the following types:

Address spoofing attack: An attacker uses the IP address of host A to send Neighbor Solicitation (NS), neighbor advertisement (NA) or Router solicitation (RS) packets to host B or the gateway. Host B or the gateway then modifies their ND entries. As a result, host B cannot receive packets or communicate with other hosts. In addition, the attacker can intercept the packets of host A to obtain the game and bank passwords of host A. Host A will suffer a huge loss.
RA attack: An attacker uses the IP address of the gateway to send the Router Advertisement (RA) packet to hosts. The hosts then modify their ND entries or record incorrect IPv6 parameters. As a result, the hosts cannot communicate with each other.

Huawei switches provide the ND snooping function to prevent ND attacks.

Benefits

Reduces costs for network operation and information security.
Provides users with stable services on a secure network.