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What is iceweasel?

Iceweasel is a fork [from Firefox] with the following purpose :

  1. backporting of security fixes to declared Debian stable version.

  2. no inclusion of trademarked Mozilla artwork (because of #1 above)

Beyond that, they will be basically identical. (quoting Roberto C. Sanchez post in debian-devel mailing list)

How to install Iceweasel (Firefox)

Iceweasel can be installed from the Debian repository with

and native language versions such as iceweasel-l10n-fr are also available.

Nevertheless a newer backport from the Debian Mozilla team is usually preferable. The Wikipedia explains some of the terminology.


The plugin directory is

while Debian-based xul-ext plugins can be found at

or something like

/usr/lib/mozilla/extensions/{ec8030f7-c20a-464f-9b0e-13a3a9e97384 (this is of xul-ext-https-everywhere)

for more info on iceweasel plugins, refer to the plugins section of the Mozilla page.

User Agent String

IceWeasel's user agent strings (at the time of writing... ) is :

Some application are checking the browser's user agent string, which prevent you from accessing the site. You can change the user agent string manually or with the User Agent Switcher plugin.

You can use the User Agent Switcher plugin, then download a UA profile :


To change the user agent string manually so that your browser is identified as 'Firefox' instead of 'Iceweasel'. Do the following.

Debian-Mozilla site

This is a resource where you can get the latest iceweasel release which would eventually make it way into Debian's experimental, unstable and finally to testing and then stable. Usually the releases make their way to Debian unstable and then go downwards while the beta versions are released to experimental. Most of the aurora releases can be found at the repo.

SSL / Secure Connection warning

The message

Can be disabled. see :


  1. My iceweasel is consistently crashing on a website
  2. First run iceweasel without loading any extensions or plugins and see if the problem persists. This can be done by using the -safe-mode option

    MOZILLA_DISABLE_PLUGINS=1 iceweasel -safe-mode

    mv ~/.mozilla/firefox/ ~/old_firefox
    iceweasel &

Unsupported Browser Error

See also