Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

In IPv4 world, when you want to talk to another computer, you ask which MAC address claims a given IPv4 address, the arp who-has ... tell ... exchange as per tcpdump, and a cache of such mappings from IPv4 to MAC addresses is usually available though arp -an.

What about IPv6, with manual configuration? IPv6 addresses don't show up on arp -an.

How does one computer discover another one over IPv6 within the same prefix?

share|improve this question
up vote 1 down vote accepted

Neighbor Discovery Protocol (NDP) is the IPv6 equivalent of the Address Resolution Protocol (ARP), and on the Unix flavors I'm most familiar with (mostly BSDs) the ndp(8) command is the IPv6 equivalent of the arp(8) command.

The command-line options for ndp are often the same as for arp, so ndp -an does exactly what you'd expect.

share|improve this answer
And ip -6 neigh under Linux. See this question – Dubu Jul 19 '13 at 9:46

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.