Linux tool for IPv6 unsolicited neighbor advertisements

Unsolicited neighbor advertisements is necessary to facilitate rapid service address takeover in a HA cluster. For IPv4 (ARP) you can use "arping -U", but so far I've had no luck finding any tool that can do something similar for IPv6.

EDIT: After searching more maybe the question is: Is this tool needed for IPv6? To me it looks like NDP should be able to solve this by it self.

I've been investigating this too. So called Unsolicited Neighbor Advertisements are still required with NDP, see:

https://www.rfc-editor.org/rfc/rfc2461#section-7.2.6

On Debian based systems you can use ndsend which you can install as follows:

apt-get install vzctl

parasite6 and fake_advertiser6 are both part of THC-IPv6 They look like they would generate the necessary ICMPv6 packets to force L2/L3 mapping changes.

You may also want to look at libndp:

ndptool -t na -U -i ${int} -T ${ipv6addr} send

As per my paraphrasing of the man page:

-t na - Send a "NA" or Neighbor Advertisement (equivalent of an ARP response "xyz is at").

-U - this is unsolicited (nobody asked for it).

-i ${int} - which interface to send it on.

-T - What is the target address in the NS/NA message.

send - to trigger sending (the other option is simply monitor).