IPv6

Feature	Benefit	Challenge
Larger address space	IPv4 address space is nearly exhausted, while many more networks and devices (such as phones or IP-enabled mobile devices) will need to be connected to the Internet.	Tracking IPv6 addresses with a spreadsheet is as practical as tracking IPv4 addresses. The large number of devices concomitant with the large number of addresses may make a spreadsheet approach impractical. Determining the next available network will not be trivial.
Address families	Headers support extensions and options such as authentication and encapsulation
Extension Headers	Unicast, anycast and multicast capabilities
Jumbo frames	Enhanced streaming video capabilities
Neighborhood discovery	Find the closest instance of a resource
Path MTU discovery	In IPv6, path MTU discovery is delegated to the end points to increase efficiency and avoid IP fragmentation
Multicast improvements	Enhanced multicast support with vastly increased address space and more efficient mechanisms	Unlike IPv4, IPv6 networks are not limited by broadcast. IPv6 multicast allows for the creation of larger, flatter networks that will need to be managed and tracked differently than with IPv4.
IP mobility	Enhanced support for mobile IP addresses and IP-enabled mobile devices
Simplified routing	Simplified packet header and packet forwarding process for more efficient end-to-end routing
Quality of Service (QoS)	Flow labeling capability for QoS, to provide better voice over IP (VoIP), video and games.
Security	Extensions for authentication and security, and built-in IPsec mandatory for all IPv6 devicesIPv6 implements network-layer encryption and authentication via IPsec
Multiple IP protocols per client (IPv4 and IPv6)		During the transition from IPv4 to IPv6 organizations will need to manage “dual-stacked” IPv6 and IPv4 networks. A single client may have both an IPv4 and an IPv6 address associated with it.
Length of IPv6 addresses		IPv6 addresses are 128-bits long (four times longer than IPv4 addresses) and are represented in hexadecimal, a format that is not human-friendly. For IT staff and network administrators accustomed to managing and memorizing IP addresses, the length of IPv6 addresses will be a challenge.
Multiple IPv6 addresses per interface		Three to four IPv6 addresses may be required per IPv6 interface, not counting the multicast addresses.
Address assignment	Stateless auto-reconfiguration of hosts allows IPv6 host to configure automatically when connected to a routed IPv6 network.	There are no static IP address assignments with IPv6. An IP Address Management (IPAM) product becomes essential.

See also: IPv6: The Next Generation Internet

Planning for IPv6 by Silvia Hagen

THC-IPv6 Attack Tool is a toolkit that attacks the inherent protocol weaknesses of IPv6 and ICMP6 and it includes an easy to use packet factory library.

ipv6 test tests your internet connection or tests a web site’s ability to handle ipv6 connections