A long time ago, at least in the context of the Internet – we used to call proxy servers – gateways. In fact the first WWW gateway was created at CERN by the World Wide Web team led by Tim Berners-Lee. Yep that BernersLee – the man who invented the World Wide Web !
So how can we define these gateways, what do they actually do? Well the most common description is that they are devices which forward packets between different networks. Of course sometimes these networks are fairly different so the gateways need to translate protocols before they forward them on. The difficulty here was that two distinct types of devices were being grouped together under the title – gateways – which needed defining.
The first type were Internet gateways which acted both as a firewall and a gateway to the internet. These would sit in front of secure private networks and allow access both inbound and outbound – these were defined as proxy servers. The other type were information gateways which usually acted on behalf of a server rather than the client. These were defined as ‘gateways’ although some call them reverse proxies just to keep it slightly confusing.
So there are even quite a few different types of proxy servers, ranging from the one page web proxies you’ll find on loads of web sites, to big corporate proxy servers which you use to access the internet from work or college.
There are however some common properties that all proxies should share –
First of all they should be transparent. That is to say they should not affect the end result, the client should receive exactly the same result from the web site whether you use a proxy or not.
Second, the decision to use a proxy should be instigated and controlled from the client. Although in most corporate networks this is true – the use of a proxy is normally hard coded in to the configuration. Most Windows clients will enforce the browser to surf through the corporate network, use specific DNS settings and cache pages on a proxy. Next time at work or school if you look in your browser under connections you’ll probably see a proxy server address set here which you cannot alter. (Under IE you’ll find it under Internet Options/connections/LAN settings).
Finally the last main property is that the destination server or web site should be completely unaffected by the use of a proxy server.
These three definitions are however slightly under threat particularly because of the increasing use of geolocation. This technology targets and controls content based on the geographical location of the client. However if you surf through a proxy server, then it is the location of the proxy that determines what you can access or see. This is why proxies are becoming so popular – if you have access to the right proxies you can access any content you like. For instance if you want to access BBC Iplayer and you live outside the UK you’ll have your access blocked. However if you connect through a UK proxy server, then you’ll be considered a UK surfer and be allowed to use it.