Neighbor Discovery Protocol

The Neighbor Discovery Protocol (NDP) is a new messaging protocol that was created as part of IPv6 to perform a number of the tasks that ICMP and ARP accomplish in IPv4. Just like ARP, Neighbor Discovery builds a cache of dynamic entries, and the administrator can configure static Neighbor Discovery entries. The following table shows the IPv6 neighbor messages and functions that are analogous to the traditional IPv4 neighbor messages.

 

IPv6 Neighbor Messages Analogous to IPv4 Neighbor Messages

IPv4 Neighbor message

IPv6 Neighbor message

ARP request message

Neighbor solicitation message

ARP relay message

Neighbor advertisement message

ARP cache

Neighbor cache

Gratuitous ARP

Duplicate address detection

Router solicitation message (optional)

Router solicitation (required)

Router advertisement message (optional)

Router advertisement (required)

Redirect message

Redirect Message

To configure NDP, navigate to the Network > Neighbor Discovery page.

The Static NDP feature allows for static mappings to be created between a Layer 3 IPv6 address and a Layer 2 MAC address. To configure a Static NDP entry, perform the following steps:

1
On the Network > Neighbor Discovery page, click the Add button.

2
In the IP Address field, enter the IPv6 address for the remote device.
3
In the Interface drop-down menu, select the interface on the firewall that will be used for the entry.
4
In the MAC Address field, enter the MAC address of the remote device.
5
Click OK. The static NDP entry is added.

The NDP Cache table displays all current IPv6 neighbors. The follow types of neighbors are displayed:

•
REACHABLE - The neighbor is known to have been reachable within 30 seconds.
•
STALE - The neighbor is no longer known to be reachable, and traffic has been sent to the neighbor within 1200 seconds.
•
STATIC - The neighbor was manually configured as a static neighbor.