Time flies. Although it was over 18 months ago, it seems just like yesterday that a small Czech provider, SuproNet, caused global Internet mayhem by making a perfectly valid (but extremely long) routing announcement. Since Internet routing is trust-based, within seconds every router in the world saw this announcement and tried to pass it on. Unfortunately, due to the size of this single message, quite a few routers choked - resulting in widespread Internet instability. Today, over a year later, we were treated to a somewhat different version of the exact same story.

As our regular readers know, Renesys computes daily rankings of all the service providers in the world: globally, by geography, and by market segment. The rankings are a rather crude measure of size, as they are based entirely on the quantity of IP space ultimately transited by each provider. However, it's the ranking trends that are more revealing than any absolute number. Who is adding customers? Who is losing them or just standing still? All of the rankings and the reasons for any changes are updated daily and available via our Market Intelligence offering. For the past couple of Decembers (2009, 2008), we've also provided a glimpse into some of this data via year-end blogs devoted to the top global providers. Halfway through 2010, we decided to revisit this topic and highlight some recent changes: the fall of Sprint and rise of Tinet being perhaps the most interesting.

Here we go again. In March we wrote a blog entitled Accidentally Importing Censorship which described how incorrect DNS answers were returned in response to certain queries to the I-root. The problem was tracked down to a single instance of the I-root located in China. Queries to this server for domains blocked in China, such as Facebook, would return seemingly arbitrary answers. As we noted, countries, and even companies, can impose their own standards on the Internet and block anything they want. This story was only noteworthy because those blocks (via bad DNS answers) became visible outside of China. Well, guess what? We are once again seeing the Beijing I-root from outside of China.

For an advanced technology that we all depend upon, it sure seems that the Internet has more than its fair share of problems: spam, viruses, malware, spyware, phishing, worms, trojans, DDoS attacks, hijacks, DNS cache poisoning, botnets, keystroke loggers, etc. We need an entirely new vocabulary just to talk about this stuff. Most of it appears to come out of the blue, forcing the rest of the world to react. But the good news is that there is at least one problem we can do something about in advance. Unfortunately, not everyone has been taking the problem seriously enough and we are about to hit the wall.

I'm talking about the impending exhaustion of IP addresses, IPv4 addresses to be exact. Every computer on the Internet needs access to at least one unique address in order to be connected. Around the dawn of the Internet, 32-bit IPv4 addresses, which allow for 4,294,967,296 different possibilities, seemed like more than enough. This was a simpler time when computers cost millions and no one imagined a phone you could put in your pocket. As the Internet grew, it soon became obvious that the seemingly inexhaustible supply of 4 billion addresses wasn't quite enough. And so, a 128-bit IPv6-based Internet was proposed, this one with 340,282,366,920,938,463,463,374,607,431,768,211,456 different addresses. (We're not going to make that mistake again!) The only problem was that the new Internet wasn't interoperable with the old one we already knew and loved. Without a Y2K-type hard deadline to focus on, we kept barreling along toward the edge of the IPv4 cliff. Now that the edge is clearly in sight, this blog looks at how far we have come in adopting the not-so-new-anymore IPv6 Internet and, perhaps more importantly, how much further we need to go.

The Internet infrastructure has been having a bad month. Not as bad as, say, the world's aviation infrastructure, but bad enough.

First, Chinese Internet censorship leaked out to a few massively unlucky users of the I root server. Then China Telecom failed to filter someone who leaked thousands of hijacked routes to other people's networks through them, probably by accident.

And then, inexplicably, Forbes went where no one had gone before (with a wink to Wired), and asked whether China might actually be testing a "cybernuke".

At first, this irritated me. Journalists and bloggers and blogger-journalists are fanning the flames of US unease about the growing role of China in world affairs. But then I realized that I could probably make tens of thousands of people read my blog, too, by jumping on the bandwagon. By all means, then, grab an MRE and hunker down in your Internet bomb shelter while I try to answer some of the obvious questions that came our way in the wake of the Forbes article:

• How would anyone build a cybernuke? What is that?
• Could a single actor, state-sponsored or otherwise, actually take down the global or regional Internet infrastructure of 2010, disrupt financial markets, throw civilization into chaos?
• How do I get my cybernuke movie screenplay optioned by Jerry Bruckheimer? His people won't return my calls.

With advancements in hardware and software, sophisticated filtering technologies are increasingly being applied to restrict access to the Internet. This happens at the level of both governments and corporations. Renesys is headquartered in the "Live Free or Die" US state of New Hampshire. In our small town of roughly 10,000 folks, we know of a local company who tries to restrict non-work related (e.g., shopping) websites from their employees. Unfortunately, someone who works there can't read about Amazon's cloud computing as a result — a small bit of collateral damage. Entire countries act in much the same way. The OpenNet Initiative keeps track of such state-sponsored restrictions and publishes interesting maps based on the level of filtering by topic. But given the open nature of the trust-based Internet, one country's restrictions, if not handled very carefully, can easily foul the global Internet nest we all live in. This blog is about one such story of Internet restrictions in China becoming visible (seemingly at random) from other parts of the world and going undetected for 3 weeks. Given the increasing complexity of this technology, the difficulty in controlling a very open Internet, and the strong desire of some to do just that, this could be a harbinger of things to come.

As Iran celebrates the anniversary of the 1979 Islamic Revolution, it seems like an opportune time to look in on the evolving state of their Internet connectivity. When we last looked, after the disputed elections in June 2009, the picture was one of uneasy stability: logically diverse but physically constrained transit via the United Arab Emirates, backup transit via Turkey. Today, a third way out of the bottle is visible in the routing table: substantial amounts of Internet transit have materialized through a Russian provider. And there, in those obscure entries in the global Internet routing table, may lie echoes of Iran's larger geopolitical strategy.

As our faithful readers know, Renesys monitors routing on the global Internet in real time and uses that information in a variety of ways. For example, we can instantly let you know which networks a hurricane has disabled or even tell you when a war has left things pretty much as they were. In short, we keep an eye on the Internet, the entire Internet, but this is all done at the level of IP addresses and the paths they follow.

The recent attack on Twitter got us thinking. Maybe we should be keeping an eye on a few more things? While your IP addresses and routes to them might be completely stable, the average user doesn't know about those. In other words, when was the last time you typed ...
    http://216.239.59.104
instead of ...
    http://www.google.com
into your browser?

What if someone manages to point your domain name to some other IP addresses? You would still be operational as far as the Internet routers were concerned, but no humans would probably be reaching you. And that's the problem we'll briefly consider in this blog.