The transition to IPv6 is growing more and more desperate…
It’s time to switch!

IPv6 is the next generation of web addresses which will eventually replace the current IPv4 system. The reason this next generation of web addresses was designed is because we are running out of addresses.

IPv4 is a 32bit address.
It supplies about 4,294,967,296 (4.3 billion) addresses.

IPv6 is a 128bit address
It supplies an astonishing 340,282,366,920,938,463,463,374,607,431,770,000,000 addresses!

The last blocks of IPv4 addresses were allocated just recently and it won’t be long before we hit complete exhaustion.

So besides the number of addresses is that the only difference? No, the entire layout of the IP address had to be changed too, because they could no longer be separated by dots otherwise the address would become far too long.

A typical IPv4 address looks like this: 167.223.172.138

      167.223.172     .         138
|_  Network Prefix _| . |_  Interface ID  _|

The subnet is not included as a part of the main address, and might look something like 255.255.255.0.

A typical IPv6 address looks like this: 2001:0d38:3d4a:0025:0000:0000:acbd:ea11

  2001:0d38:3d4a    :      0025      :   0000:0000:acbd:ea11
|_ Global Prefix _| : |_  Subnet  _| : |_   Interface ID    _|

Now the length may be confusing at first, it certainly confused me and still does! The total length must always be 128 bits, and it is also hexadecimal now rather than just decimal. That means it can contain letters from A to F to indicate numbers 10 to 15. But you can take shortcuts to make the length shorter.

For example, you can shorten blocks of zeros with colons.

2001:0d38:3d4a:0025:0000:0000:acbd:ea11

becomes

2001:0d38:3d4a:0025::acbd:ea11

Localhost, the IP used to access your own computer is

0000:0000:0000:0000:0000:0000:0000:0001

Shortened to remove blocks of zeros it becomes

::1

Easy!

However you must remember that the double colon “::” to indicate blocks of zeros can only be used once in an IP. If you want to check the validation of an IPv6 address, you can try this site: http://www.intermapper.com/ipv6validator. It also gives you a shortened “best representation” version too to save you some work.

Now that the structure of the IP has been explained, how does it affect you? Well pretty soon the world is going to run out of IPv4 addresses. When that happens, no more IP’s can be given out and some computers or other devices won’t be able to get online in the conventional way. The only way around that is by using NAT (Network Address Translation) which is what your home router does. It uses one external IP and then gives your computer private internal IP addresses that are only used for private use, and can’t be accessed outside your network. This is OK for most home broadband, but for servers and the likes, this isn’t possible because NAT can’t determine where the packets need to go unless the machine behind it asked for the data in the first place. Servers work the other way around, you request data from the server and it sends it to you.

That is the primary reason we need to switch to this next generation of IP addresses. However despite the urgency of switching, most ISP’s in the world still haven’t made the move. The reason behind this is cost. Not all of the equipment on the network at present supports IPv6, so it will have to be upgraded at a huge cost to the ISP. Most top level providers have had IPv6 implemented for some years now, but smaller broadband ISP’s just don’t have the money.

Temporary solutions are IPv4 to IPv6 gateways which many ISP’s have set up to aid the transition. These work by encapsulating IPv6 packets in IPv4 and then the gateway translates them to true IPv6, but those often fail or packets never reach them so switching to native IPv6 is the only real solution. Now is the time to start thinking about making the switch because it’s already far overdue. Most modern home routers have IPv6 support, so for many there will be no need to worry. Having a modern operating system on your computer is your only other concern, but Windows XP and higher support IPv6. The effort needed by the consumer is minimal, but for ISP’s, the job is much larger.

Some large organisations such as Google and Facebook are enabling IPv6 for one day on their network as part of World IPv6 Day to test and encourage the IPv6 transition. The effects on SEO should be minimal and the only impact that should be seen are some possible slow downs as computers try to connect over IPv6, fail, and retry on IPv4 on networks with no IPv6 support.