IPv6 offers a much larger address space than that of its IPv4 counterpart. The standard /64 IPv6 subnets can (in theory) accommodate approximately 1.844 * 10^19 hosts, thus resulting in a much lower host density (#hosts/#addresses) than their IPv4 counterparts. As a result, it is widely assumed that it would take a tremendous effort to perform address scanning attacks against IPv6 networks, and therefore IPv6 address scanning attacks have long been considered unfeasible. This document analyzes how traditional address scanning techniques apply to IPv6 networks, and also explores a number of other techniques that can be employed for IPv6 network reconnaissance. Additionally, this document formally obsoletes RFC 5157.
You can download it from the following link: https://packetstormsecurity.com/files/download/118809/draft-ietf-opsec-ipv6-host-scanning-00.txt
Source: https://packetstormsecurity.com/files/118809/Network-Reconnaissance-In-IPv6-Networks.html