ref：http://www.enigmagroup.org/articles/view/Web%20Hacking/12-Spoofing-your-useragent-in-Firefox

如何设置Firefox伪装的浏览器名称——

In certain places, or certain missions, im sure you have run into a little barricade saying you must be using a certain browser type to get in.  

And most of the time, the browser is made up. 

But anyways, Im going to show you how to make it so you can get past these road blocks. 

Ok so here is N00bhacker27. He stumbles upon a webpage that only allows people using the <b>1337h4x0r</b> browser in. 

To do this (in Firefox of course) open up a new tab. And in the address bar, type <b>about:config</b> 

You should get a huge list of things. This is to be expected. 

Now right click on any thing listed, and select <b>NEW</b>. From there, select <b>STRING</b> 

You should get a popup box saying <b>Enter the Preference Name</b>. Type: 

<b>general.useragent.override</b> and hit enter.  

Then, at the top, it will say <b>Enetr String Value</b> 

This is where you put the name of the browser you need to get it. For N00bhacker27, he enters <b>1337h4x0r</b>. 

N00bhacker27 then goes back to the page before that would not let him in, and voila! He is now able to enter! 

This is very useful, and you need to know this for future missions and reference. If you have any questions, pm me in the forums. 

(After you no longer need to get in the restricted page, go to About:config, find the string you created, right click it, and click reset. You will not be spoofing anymore)

Spoofing your useragent in Firefox