User Agents
UserAgents are user by browsers to let the website that they're visiting who they are, so the site can load browser-specific code. However, by spoofing our UserAgent, we can trick websites into thinking we are someone else. A large list of UserAgents is available here. Save as .xml,then import it into User Agent Switcher.
Spoofing your UserAgent has three main uses.
Anonymity
We can throw off some attempts at telling who we are, by by pretending to be a different version or browser. If the site is looking for someone using Firefox 2.0.12, and you look like Opera 9, they won't notice you. However, this method isn't foolproof. More advanced sites can find out who you are, using methods such as examining your http headers, or by using Javascript. More info here
Pretending to be IE
Some sites claim to only work using Internet Explorer. This is usually complete crap, so by changing our UserAgent to IE, we can get around this.
Gaining Access
Have you ever searched something on Google, clicked a link, and been given an 'access denied' error? The reason for this is that same sites allow Google to access places a normal person can't. We can use this to our advantage, by pretending to be one of Google's spiders, which will allow us to see the protected content. Certain versions of IPB are vulnerable to this, and one major example was the cheating site msxsecurity.com (before it closed down), in which you could gain access o the VIP area with this trick. The UserAgent to use when impersonating Google is: Googlebot/2.1 (+http://www.googlebot.com/bot.html)
Examples
