Information
ND (Neighbor Discovery) Snooping is a security feature that enhances IPv6 network integrity by monitoring and validating IPv6 neighbor discovery messages. It prevents malicious activities such as ND spoofing and rogue advertisements. ND snooping drops invalid ND packets, and combined with IPv6 Source Lockdown, blocks data traffic from invalid hosts. ND snooping learns the source MAC addresses, source IPv6 addresses, input interfaces and VLANs of incoming ND messages and data packets to build IP binding entries.ND snooping drops ND packets for the following reasons:
- If the Ethernet source MAC address does not match the address in the ICMPv6 Target link layer address field of the ND packet.
- If the global IPv6 address in the source address field does not match the ND snooping prefix filter table.
- If the global IPv6 address or the link-local IPv6 address in the source IP address field does not matchthe ND snooping binding table.
The feature ensures that only legitimate IPv6 devices can communicate on the network by maintaining a trusted ND cache. This reduces vulnerabilities and strengthens Layer 2 and Layer 3 IPv6 communication.
NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.
Solution
The following are sample VLAN configurations of globally enabled ND snooping -
switch(config)# nd-snooping
switch(config)# vlan <vlan-id>
switch(config-vlan-id)# nd-snooping
switch(config-vlan-id)# exit
switch(config)#
Impact:
ND Snooping improves network security by mitigating IPv6-based attacks, enhances device discovery accuracy, and ensures reliable communication between endpoints in IPv6 environments.