Australia’s Federal Court this week ordered internet companies to block five file-sharing websites, including well-known torrent hub, The Pirate Bay. As with all things online, however, this isn’t a simple task – blocking these few pages will have a massive ripple effect on a number of other (less-notorious) websites.

It just so happens that ThePirateBay runs on Cloudflare, a very popular content delivery network. A content delivery network (CDN) is a globally distributed group of servers all located in different parts of the world, designed to help speed up website traffic. In non-internet speak, think of it as a fast food restaurant. All the food (content) is the same around the world, but there’s a restaurant is just around the corner so you can get to it quickly, rather than having to travel to London. Instead of food, CDNs are used to help you get websites faster, so they respond quicker, and you can download faster.

As a rule most CDNs will share IP addresses with multiple sites, this is called virtual hosting. It is a very common practice, and helps to reduce the number of IP addresses that are used. This is important to note, because there are only two ways you can block a website. One is via DNS and the other is via IP address.

Blocking a website via DNS means your ISP will simply stop pointing traffic to that particular address, which might be enough to prevent some people from accessing the site. But nothing says you need to use your ISP’s DNS server (while it is what your ISP does by default, it is very easily changed). Instead, you can either use one of the many publicly available DNS servers hosted online, or just run your own locally. Which is what I have done for the last 10 years.

So the only real solution is to block a website by its IP address, and this is where everything falls apart. Today, as I mentioned, ThePirateBay uses a third party CDN, and has an IP address that is assigned to Cloudflare. Cloudflare, like most CDNs, shares its IP addresses among customers, so banning the IP for ThePirateBay may also impact some of Cloudflare’s other users – and these aren’t trivial. These are customers like Cisco, one of the world’s largest IT hardware providers, and the NASDAQ stock exchange. 46% of all internet traffic is web traffic and a large amount of that web traffic comes from CDNs.

Some of the world’s largest sites – including most of the world’s news websites, as well as Reddit, Netflix, Apple and Facebook – all use CDNs to distribute content. Most of these sites share IP addresses and many have thousands of them. Akamai is another popular CDN, which shares IP addresses between many of its customer’s websites, including news.com.au. If it was decided that news.com.au should be banned (as it was decided it was bad for everyone in Australia), an IP address restriction would also block sites including NBC, Apple, Facebook, Malaysian Airlines, and Qantas.

This isn’t just a hypothetical possibility, but something that has already occurred when ASIC blocked 250,000 websites while banning two foreign websites called Global Capital Wealth and Global Capital Australia. This was four years ago, but there is still a massive lack of understanding on how the internet works when it comes to blocking websites. It has been proven over and over that it simply can’t be done. With literally thousands of ways to escape the ban by both the Aussie user, and the site operator, a block just wont work. I look forward to TehPirateBay being online any minute now.