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The Digital Texas Tea (IPv4)

On February 3rd of this year, the Internet Assigned Numbers Authority (IANA) who according to their website “is the body responsible for coordinating some of the key elements that keep the Internet running smoothly,” assigned the last 5 remaining blocks of IPv4 addresses to the five Regional Internet Registries. One of the five, the American Registry for Internet Numbers (ARIN) assures us that they still have a pool of available addresses and will continue to assign those addresses in accordance with documented policy. To help put the folks who get all edgy at rest they are publishing daily updates on their website linked above. All that being said I’ve still seen quite a bit of hype about the rapidly depleting quantity of available IPv4 addresses so I thought I’d take a moment to address the issues at hand.

Lets start with what exactly is going on in the simplest terms. Way back when, in the early 80’s the good folks who were putting together the internet developed an addressing system that allowed every computer on a network to reference every other computer using a unique address much like a street address would uniquely identify your home. Using four sets of digits between 0 and 255 (the maximum allowed by using 32 bits per digit) separated by decimal points they were able to create a massive amount of unique addresses. These good folks decided that certain address spaces were going to be reserved such as 127.0.0.1, 0.0.0.0, and 255.255.255.255 so after all was said and done there were roughly 3706.65 million usable addresses.

Unfortunately the good internet folks couldn’t have predicted the number of devices that would use IPv4 address space such as mobile devices, tv’s, and even some web enabled home appliances. When it was realized that the global demand for web access would far exceed the expectations of it’s creators certain measures were put in place to slow down the eventual exhaustion of the available addresses. Measures such as private networks reusing address spaces such as 192.168.1.255 then connecting several devices to the web with network address translation (NAT) basically using one address like a buildings street address and several apartments inside subdivided by apartment number. Sadly these efforts weren’t enough and with an ever increasing number of web enabled devices a new addressing system was developed known as IPv6 (version 6 vs the previous version 4; who knows(cares) what happened with versions 1, 2, 3, & 5). The problem with IPv6 is that because it uses a completely different addressing system it is not cross compatible with IPv4 which means everyone must adopt the new system for it to be successful.

IPv6 has been around for years and while most of the hardware is physically capable of supporting the traffic and a large amount of the software is capable of supporting it the global adoption of the protocol just hasn’t happened. Most business majors such as myself would blame the overall cost of making the switch. Big businesses are afraid of switching to a newer address system because it means potential clients may not be able to reach them. Oddly enough this isn’t true because most computer systems developed in the last few years can support both IPv4 and IPv6 simultaneously. Of course setting this all up and installing new compatible routers and software takes time and money that most companies might consider a waste because what they have is working for them now.

This is all good in theory, oddly enough I watched a great case study as Iowa State University started implementing IPv6 throughout campus and there were plenty of issues. While on campus I spent most of my time in three buildings accessing computer resources physically and remotely between those buildings. While working on my laptop in an IPv4 building I could access all of the resources in that building and the other two; if I moved to either one of the other two IPv6 enabled buildings (still had IPv4 access) while in theory my system should have worked I was occasionally unable to reach certain systems that were only using IPv4. Why did this happen? For a few reasons, my operating system was configured in such a way that it preferred IPv6 communication over IPv4 so if it was on an IPv6 enabled network it broadcast its requests to the IPv6 network instead of the IPv4 network if no response was received it would fail over to IPv4 and hopefully find the desired resource. Certain router configurations prevented this failover process from happening so unless I disabled IPv6 on my machine I could not access IPv4 resources. This in a nutshell is what’s holding the world back from IPv6 (in my opinion).

Another (less likely) consideration goes right along with the title of this post, it’s the basic law of supply and demand. What happens when a finite resource such as oil or IPv4 addresses has an increasingly large demand and an ever shrinking supply. The price goes up. Registries can charge more for the last remaining blocks of addresses and as that filters down the pipes hosts can eventually charge more per year for every IP address they assign. If the powers that be are careful the can do this until it is no longer feasible then switch over to IPv6 and continue to sell IPv6 address space off at an inflated price. But that’s all just food for thought.

Oddly enough in all of this hype I came across more than a few posts that stated that after switching to IPv6 we would have more than enough addresses, Focus even going so far as to call it “an inexhaustible amount of IP addresses.” Who ever said history is doomed to repeat itself seems to be spot on. We cannot assume that this is a permanent solution and while it is a good solution for the time being, increasing the volume of available addresses dramatically, we will eventually run out again so we need to be thinking about another stop gap or maybe even a solution.

So what does this mean for us right now at this very moment in time? As individuals we should be conscious of our IP address utilization. Use NAT’ing when ever practicable and avoid un-necessarily using public IP address space. System admins should do the same; use virtual hosts when possible to avoid using multiple addresses on individual servers. Most important of all for system admins, make sure all of your network resources are IPv6 compatible and configured properly to use IPv6; eventually the switch is going to happen and it’s not going to happen seamlessly unless everyone gets onboard, starting with the hosts.

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