IPv6, which devices have all to support it in the chain?

[switch_abx]

which devices have all to support IPv6 to allow IPv6 based packets to go through the network (LAN, WAN)?

This is is clear:
1. router
2. hardware firewall

But do these also need to support IPv6?
3. switch?
4. NIC (Network Interface Card)?

Of course, the ISP and the OS (e.g. VISTA, XP, Windows Server 2008) should also support

[shaihulud]

Well, this is a bit tricky because you are asking intrinsically. Technically an IPv6 packet can be encapsulated via IPv4. Therefore making it work with existing infrastructure.

To answer your question you basically only need to worry about layer 3 and the WAN IPv6 support. This means devices that are other layers such as switches and NIC's you will not need to worry about. Switches only forward frames and do not care about the packet (layer2). This is will change if the switch is capable of layer 3 and 4, and will be operating in an IPv6 environment. NIC's are able to support IPv6 due to the fact that the operating system is what does the work for layer 3. The packet, before it is sent, is encapsulated by the Ethernet layer (layer 2) which before was at layer 3. The operating system is responsible for doing this part. So if the OS supports IPv6 then it will be able to work with it-technically speaking.

A firewall has to support the applicable layers. If there is no support then you are not IPv6 compatible/capable. However, there are plenty of Open Source firewalls that *can* add IPv6 support easily if not supported. If it is a tunneling system NAT and port issues can occur due to protocol 41 encapsulation.

[switch_abx]

shaihulud, thanks so much! Much appreciate your insight.