Department of Engineering

IT Services

Configuring Firefox on the Central System

This page deals with the Firefox WWW browser which is on the linux teaching system. It shares many features with the older Mozilla browser, but the details of configuration differ. Firefox already has good support for some advanced web facilities (such as MATHML), and we've installed some extra facilities but you may wish to personalise your set-up further.


  • "Themes" let you to change the look and feel of the user interface (other programs often use the term "skins" instead of "themes"). You can download them from Firefox's themes page, or look in the Tools/Add-ons menu.
  • "Extensions" are small add-ons that provide extra features. See Firefox's Extensions page for a list, or look in the Tools/Add-ons menu.
  • .plugins"Plugins" provide significant extra functionality so that the browser can display more types of files (movies, PDF files, etc). The common plugins for Firefox are on their plugins page. We've installed most of these. To find out which plugins you have, use the Edit/Preferences/Content panel and press the Manage button of the Filetypes. You'll get a panel similar to the one of the right. Note that some files can't be displayed within the browser window, but can be displayed by another program (a "helper function") in a separate window. Alternatively you can type about:plugins in the file/URL field (where you'd normally type a URL).
  • More advanced options can be accessed by typing about:config in the file/URL field. The Help/Contents/Customisation menu option has some documentation.

Disc-space quota

  • Browsers keep local copies of recently visited pages to save time if you want to see them again. You can set a limit on how much space is devoted to storing old pages. If this limit is 50Megs and you only have 10Megs of file-space allowed for your activities, you'll find that the browser will soon use up your quota of disc-space.

    In the Edit/Preferences/Advanced/Cache menu options you'll find a "Clear Cache" option (the "Cache" is the store of old pages) and a way to limit the Cache size. Clearing the Cache and setting the limit to 3 MB should help with quota problems.

  • Removing old files - If you've run Netscape in the past you'll have lots of files you'll never need again. The first time you run Firefox it will try to copy over your bookmarks, etc. After that, you may wish to remove the old Netscape files (which may occupy many Megs). You can do this by typing the following carefully (use copy-paste) on the command line (having first quitted from any Mozillas and Netscapes that you may be running)
      cd ~ ; rm -fr .netscape

Mozilla Firefox 3

The newest Firefox stores configuration info differently to how older versions did it. Details are on the Profile folder - Firefox page.

If you find a file called urlclassifier3.sqlite under your ~/.mozilla/firefox folder, don't be surprised if it's more than 55M big.


By selecting the Organise Bookmarks option in the Bookmarks menu you can reach a panel that lets you load and store bookmark files. This is useful if you want to back-up your bookmarks, or if you want to transfer bookmarks between browsers.importexportbookmarks If firefox crashes and seems to lose bookmarks you may still be able to recover them by using the Restore or Import commands. Some places to look for bookmark files are

  • ~/.mozilla/firefox/*default/bookmarkbackups/
  • ~/.mozilla/firefox/*default/oldbookmarkbackups/
  • ~/.snapshot/ (which contains various backups of your files)

See also

Also the following pages may help with specific issues