Finally IPcalypse has came

[Wguy2008]

It's official , there are ranges of IPv4 that may be reserved for new companies, there is only officially and globally deploy the protocol IPv6 . In short, not only have increased the number of IPs available, change the whole philosophy and both concepts like configuration are not very intuitive. As PIs implement it natively, in principle, most Linux-based routers are already capable of using IPv6 or may be covered with just a software update. A priority this is not a problem for most users or ISPs exist, since they have already purchased their ranks and unless they are exhausted by now can get by; However it is a problem for new ISPs and anyone who wants to buy a hollow on the Internet. Basically what has happened is that the entire range of IP version 4 which goes from 0 to 255, divided into 4 segments: 0.0.0.0 is sold. To date, this situation had cheated by using NAT on the local networks.

NAT operation is very simple, it forms a subset of networks, linked together by a router, for the ranks of local networks reserve 3 segments: 10.0.0.0 (class A), 172.16.0.0 (class B) and 192,168 .1.0 (class C), the local network computers IPs will be within these ranges. When seeking access to an external ip range assigned to the router will ask the network, which has 2 network cards (hereafter referred to as interfaces) allowing it to bridge.

[Wguy2008]

In other words, now all requests from any computer on a local network from the Internet as they are coming from the same IP. IPv6 is new, in every sense, first pass IPs comprising 0 to 65535 divided into 8 segments, ie MANY. The form also represent change, they opted for simplicity and compact hexadecimal numbers. In addition there are many ways to write the same IP, I recommend taking a look at the explanation is on Wikipedia (yes, as usual this post is not very technical at the moment, only conceptual and that this issue could extend to several posts).

The philosophy changed, like so many IPs available, the idea is that all devices are accessible directly from the Internet , you can even connect to the toaster in your home with your mobile. Thus no longer the concept of NAT, but you can make some unofficial hack out there (do that only have IPv6 router and the other teams use a http proxy through it, or assign a range of local and make IPv6 a pseudo-nat).

[Wguy2008]

The parallel network stacks! What does this mean? to have a dual IPv4 and IPv6 means that the team must have configured two separate firewalls, one for each protocol. Think about it graphically as you have just install a newer network card and wired in parallel to one you already had. And there's more, while the ISPs do not implement IPv6 natively, can be used by 6to4 tunnel. What is done is to pass IPv6 traffic encapsulated in protocol 41. The first step would enable the IPv4 firewall:

echo "Enabling IPV6 ..." 
iptables-I INPUT-j ACCEPT-proto 41

To enable the tunnel depends on whether you have static or dynamic ip. If dynamic you will have to give you high in any service that allows you to use the tunnel, looks like the old way with the modem PPP connection, launching a customer who creates a TAP interface on the computer. If you have a static IPv4 and if we have within the team because the router is in bridge mode, we can create the bridge natively 6to4. Is complex to understand all the parameters and why, and manuals are created by internet, post proper detail here everything that I have not seen or struggled to find me there.

[Wguy2008]

Here is an Example

# In / etc / network / interfaces would define something as follows: 

auto tun6to4 
inet6 tun6to4 iface v4tunnel 
address 2002: YYYY: YYYY: 1:: 1 
netmask 16 
gateway:: 192.88.99.1 
Any endpoint 
XXX.XXX.XXX.XXX local 
up ip -6 route add:: / 0 metric 1 dev tun6to4 
up ip -6 route add 2000:: / 3 via:: 192.88.99.1 metric 1 dev tun6to4 
up ip -6 route add 2000:: / 3 via 2002: YYYY: YYYY:: 1 metric 1 dev tun6to4 
up ip -6 addr add 2002: YYYY: YYYY:: 1 / 16 dev tun6to4 
up ip -6 addr add 2002: YYYY: YYYY: 1:: 1 / 64 dev br0 
down ip -6 route flush dev tun6to4 
up / etc/network/ipv6rules.sh 
255 ttl 
mtu 1480 

# Where it says XXX.XXX.XXX.XXX is your public IPv4, where is your place YYYY.YYYY converted to hexadecimal IPv4, the IPv6 prefix 2002 in the format indicates a compatibility and this means that we have a range of 65535 IPv6 for us all alone, until the alarm can be IP.

This will create an interface that automatically route the IPv6 traffic for us. Look at what I call the script / etc/network/ipv6rules.sh to configure the IPv6 firewall (in my case is ipv6tables, native linux kernel). Once created and launched the tunnel of the forms listed above, would fail to install a program to transfer the routes to other computers on the network, in the case of linux using radvd. If not installed and configured, only the team with the tunnel 6to4 IPv6 connectivity will, while if it is installed and configured, the other teams know how to reach the next router and be publicly visible, this is how IPv6 solves the problem of NAT (remember the typical: To go out there to use the front door pass it on!).