Thursday, 15 August 2013

The Dangers of Web Filtering

In my previous article I spoke about how the British government is rushing web filtering technology into action and how it is a dangerous for civil liberties. There are various moral and ethical reasons as to why web filtering is wrong and shouldn't be imposed and in this short article I'm going to touch on the technical reasons as to why this is dangerous.

Firstly the world wide web was designed to be a world wide system. When you visit a website like or you type into your web browser and your web browser asks a server to check what the address of actually is. It's similar to how a phone book works. Imagine you want to find out what Joe Bloggs phone number is, you know Joe Bloggs name but not his address. You look for Joe Bloggs in the phone book and when you find him in the book, you check his phone number so that you can then call him. The web works on a similar principal. The idea being that you don't need to remember a long complicated I.P address, instead you type a simple human readable address which is easier to remember.

Now imagine that Joe Bloggs works in a large shared building that your utility provider for electricity operates out of, Joe Bloggs keeps calling you to try and sell you a higher tariff service and you ask him to stop calling you. Joe repeatedly keeps calling you regardless because he's a bit of an idiot. You decide to block the shared building phone number to stop being harassed by Joe.

A few weeks later you try to call your phone company who happens to be in the same building as your electricity provider. You find that you can't call them because they share the same phone number and it has been blocked! Now imagine that when you block that buildings telephone number, it scales to everybody who tries to call that building.

This is exactly the kind of problem that web filtering can and does cause. Lots of websites share the same server which means they share the same address. If you block one address, you block all of the web sites on that same server. An example of this occurring in the real world can be read about on the BBC here.

Imagine this on a massive scale and the very infrastructure that supports the world wide web is endangered.