A user agent is a computer program representing a person, for example, a browser in a Web context.
Besides a browser, a user agent could be a bot scraping webpages, a download manager, or another app accessing the Web. Along with each request they make to the server, browsers include a self-identifying User-Agent HTTP header called a user agent (UA) string. This string often identifies the browser, its version number, and its host operating system.
Spam bots, download managers, and some browsers often send a fake UA string to announce themselves as a different client. This is known as user agent spoofing.
A typical user agent string looks like this: "Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:35.0) Gecko/20100101 Firefox/35.0".
By changing user agent, sometimes, one can get access to restricted part of a website with extra contents that normally open only to bots, or search engine crawlers. This kind of area typical example is “Member Only” forums or sites that don’t want to lose out on search engine traffic. Modification of user agent string also enable surfers to trick websites into believing that they are actually using a particular web browser or using specific system in order to avoid and disable advertising display or junk ads that targeted to specific segment of viewers of the websites only.
Once installed and restarted Firefox, simply go to Tools Sergeant Switcher, and you will see a list of user agents which you can choose. By default, there is only a few user agents listed (depending on the versions), which can be Internet Explorer 6 / 7 / 8, Netscape, Opera, various search robots such as Google bot, Minot, Yahoo Slurp and iPhone 3.0.
The second method that you can modify the user agent in Firefox is by performing the following steps, which do not require any download: To change back to the default user agent, simply right-click on the line and select Reset.
OK is a technology writer for Tech Journey with background of system and network administrator. He has be documenting his experiences in digital and technology world for over 15 years. Connect with OK through Tech Journey on Facebook, Twitter or Google+.
User agent is an HTTP request header string identifying browser, application, operating system which connects to the server. Not only browsers have user agent but also bots, search engines crawlers such as Google bot, Google AdSense etc.
If you ever wanted to make your web traffic seem like it was coming from a different browser–say, to trick a site that claims it’s incompatible with yours–you can. This allows you to request web pages intended for different browsers–or even different devices, like smartphones and tablets.
Click the menu button to the right of the “Console” tab at the bottom of the Developer Tools pane and select “Network Conditions” If you don’t see the console at the bottom, click the menu button in the top right corner of the Developer Tools pane–that’s the button just to the left of the “x”–and select “Show Console”.
On the Network conditions tab, uncheck “Select automatically” next to User agent. It only works while you have the Developer Tools pane open, and it only applies to the current tab.
To create the preference, right-click on the about:config page, point to New, and select String. This setting applies to every open tab and persists until you change it, even if you close and reopen Firefox.
To revert Firefox to the default user agent, right-click the “general.user agent.override” preference and select Reset. Microsoft Edge and Internet Explorer have user agent switchers in their developer tools, and they’re nearly identical.
To open them, click the settings menu and select “F12 Developer Tools” or just press F12 on your keyboard. The developer tools will open in a separate pane at the bottom of the window.
You can find extensive lists of user agents on various websites, such as this one. It only applies to the current tab, and only while the F12 Developer Tools pane is open.
Chris has written for The New York Times, been interviewed as a technology expert on TV stations like Miami's NBC 6, and had his work covered by news outlets like the BBC. Since 2011, Chris has written over 2,000 articles that have been read more than 500 million times---and that's just here at How-To Geek.
If websites tell you that your browser is outdated or incompatible even though Firefox is up to date, an incorrect user agent may be the cause. This article explains how to fix problems with your Firefoxuseragent so that websites work properly.
You can changeFirefox's user agent to trick websites into thinking that you're using a different browser or operating system. Websites may not display correctly or may show a message that your browser is outdated or incompatible, based on the detected user agent.
It's important to switch Firefox back to the default user agent so that websites work properly. The Application Basics section will show your current Firefox version and will include a Sergeant entry.
If you can't resolve the problem this way, follow the steps below to reset the default user agent. Type about:config in the address bar and press Enter Return.
Right-click Hold down the control key while you click on each of these preferences, if they exist, and select from the context menu. Type about:config in the address bar and press Enter Return.
You can have multiple Firefox profiles, each containing a separate set of user information. Type about:profiles into the address bar and press the EnterReturn key.
The new profile will become the default and will be used the next time you start Firefox. Note: The folder containing the files for the profile is not renamed.
Click this to make Firefox use this profile by default at startup. Click the Firefox menu at the top of the screen and select.
Click the Firefox menu and select. In the Run dialog box, type in: Firefox .exe -P You can use -P, -p or -ProfileManager (any of them should work).
You can have multiple Firefox programs installed in different locations. To start the Profile Manager for a specific Firefox installation, replace Firefox .exe in the above instructions with the full path to the Firefox program, enclose that line in quotes, then add a space followed by -P.
If the Profile Manager window still does not open, Firefox may have been running in the background, even though it was not visible. Close all instances of Firefox or restart the computer and then try again.
If you choose a folder that isn't empty and you later remove the profile and choose the “Delete Files” option, everything inside that folder will be deleted. “Don't Delete Files” is the preferred option because it saves the old profile's folder and allows you to recover the files to a new profile.
Delete Files removes the profile and its files (including the profile bookmarks, settings, passwords, etc.). Note : The folder containing the files for the profile is not renamed.
If you check this option, Firefox will automatically load the selected profile at startup. If you uncheck this option, Firefox will show you the Profile Manager each time you start Firefox, so that you can select a profile to use.
When you first open Firefox in a new profile, a Welcome to Firefox page will open, with a space to enter your email address. Enter your email address and click Continue, to create or sign in to a Firefox Account.
You can then set up Sync for the new profile so that you can share the same bookmarks, browsing history, passwords and other user data with other Firefox profiles or devices. If you already use Sync in another profile or device, enter the email address and password for your Firefox account so that your new profile can use those settings.