Does Network Discovery (rfc2461) preclude ARP sniffing? I'm debugging a system demonstrating intermittent loss of connection. It's loosing entries from the neighborhood cache while there are active connections. Does Neighbor Discovery (rfc2461) require that the neighborhood cache (arp cache) can only be refreshed by network probes? Or should the timeout normally be updated by network traffic?

> Does Network Discovery (rfc2461) preclude ARP sniffing?

No, IPv6 prevents ARP sniffing. IPv6 does not use ARP, which requires broadcast, and IPv6 does not have broadcast.

Instead, IPv6 makes heavy use of multicast, and Neighbor Discovery Protocol does many things, including replacing ARP. You should learn more about IPv6 multicast, which has flags and scopes. Also learn about MLDv2, which is what IPv6 uses instead of IGMP that IPv4 uses.