- Neighbor discovery (ND) is the IPv6 datalink protocol, ==replacing the Address Resolution Protocol used in IPv4 Ethernet.==
- Neighbor discovery is supposed to work on all datalink protocols, not just Ethernet, but Ethernet is still the most common.
- Neighbor discovery is extremely similar to ARP. The IP addresses are larger, and the state table has a few more entries.
- Unlike ARP, where entries are either present or missing, neighbor cache entries can have a few different states :
- Reachable addresses are currently live on the network.
- Stale addresses were live, but have since expired from the cache.
- Permanent addresses are either local on the machine, or special-purpose addresses that are always present.
- Failed addresses are neighbors the host has looked for but not found.
Windows ND
netsh interface ipv6 show neighbors
Unix ND
netstat -pn -f inet6 (Solaris)
ip -6 neighbor show (Linux)