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JonDoFox Features

In the following, the main features of our JonDoFox extension will be explained. They allow the user to surf the web in a more secure and convenient way.

Stay flexible and switch proxy

If you would like to surf the Web with a different (local) proxy than JonDo or without any proxy, just use the button JonDo-Proxy integrated in JonDoFox (upper left) in order to switch between different proxy configurations:

  • No Proxy: If no proxy is set, JonDoFox directly connects to the Internet. Attention: Your IP address will be sent in plain and is not hidden!
  • Custom: Using this setting, you may use your own proxy configuration. Choose NoScript: not trustworthy Preferences in order to create an individual proxy configuration. However, this is only recommended for experts.
  • Tor: If you have installed and started the program Tor you may use it as an alternative to JonDo with this setting.
  • JonDo: When this setting is active, JonDoFox sends the browser's communication data to JonDo. This option hides your IP address. JonDo needs to be separately installed and started.

Whenever you like to bypass the proxy without completely deactivating it (e.g. when downloading large files to save time and money), just open the context menu with a right mouse click on the file and choose Bypass JonDo/Tor/Proxy and Save Link As...


The Referer is one of those HTTP features that allow to distinguish different users while surfing the web and therefore, to reduce their anonymity. But that can be avoided activating our Referer management:


With it, the Referer is not simply deleted as some webservices are not available without it. Rather, the Referer will or will not be set depending on the context of a particular request. E.g. it will be set as long as a user is surfing within the same domain and will not be set if a bookmark is used to request a particular web page. This context dependent behavior ensures that no web pages will break while at the same time the Referer cannot be used to gather information to identify users.

User Agent-Management

Information regarding users surfing the web may not only be gathered analyzing the Referer but examing the individual User Agent header as well. Therefore, we built a uniform User Agent which all users of JonDo are sending along while requesting pages on the WWW. If a user wants to connect to the Tor network instead of using JonDo the User Agent is rebuilt again, this time matching the one issued by the Tor Project and its browser add-on, Torbutton. And, additionally, if someone wants to configure a proxy manually then she has the opportunity to choose between different User Agents, i.e. Unchanged (leaving the default setting), JonDo and Tor:

User Agent-Management

Mitigating cache attacks

Besides the possibility to obtain user related information examining the Referer, the User Agent and other HTTP headers, the browser cache can be exploited as well to achieve this goal. An attacker may, for instance, try to get some information out of the fact that web pages saved in the cache are loaded faster than the same, non-cached ones. Or she might try to set so-called cache cookies to identify a particular user across different domains. In order to better protect our users against this kind of attack we included the slightly modified code of the SafeCache extension into JonDoFox.
Additionally, the authentication cache of Firefox might get exploited to track users across several different domains. In order to defend against this kind of threat we discard authentication information sent by/to 3rd party elements. In the JonDoFox settings panel you will find a corresponding hint:

Settings Header



Defending against Plugins

Plugins can circumvent the proxy settings of JonDoFox which makes them especially dangerous while surfing anonymously. Therefore, all plugins are deactivated by default in JonDoFox' JonDo mode. Only Flash is still available due to its widespread use. The setting governing this behavior may again be found in JonDoFox' settings panel:

Settings Header



Detecting faked SSL-Certificates

In order to provide a better protection against faked SSL-certificates we enhanced the functionality of the Certificate Patrol extension and included it into JonDoFox (as can be seen in the JonDoFox settings panel):

Settings Header


Certificate Patrol

On the one hand, this allows users to check the fingerprint of a certificate very easily. On the other hand a helpful dialog is shown to the user indicating whether there could be something wrong with an updated certificate, thus supporting the user to avoid information leaks due to faked certificates and man-in-the-middle attacks.

If you keep this feature enabled a database, CertPatrol.sqlite, is created in the directory of your JonDoFox profile. It stores all websites visited via HTTPS together with some information about the SSL certificate of the web server. A web server has no means to get that saved data.

We furthermore included a way to help the Electronic Frontier Foundation (EFF) to collect SSL certificates. That effort aims at making the web a safer place in the long run and may be supported very easily by JonDoFox users now.

Getting temporary E-Mail addresses

With JonDoFox you have the opportunity to get temporary E-mail addresses conveniently. In order to do so right-click on a text field in which you want to get the E-mail address and choose the following entry out of the menu popping up:

Temporary E-mail addresses -- context menu

Thereafter, clicking on 'Request a temporary E-mail address' the requested E-mail address will get inserted into the text field and your account gets opened in a new tab. If you want to decide by yourself which provider of temporary E-mail addresses you would like to use there are two options available: The first is hovering over the '>' shown on the image above. That allows you to choose a provider ad-hoc. The second option is using the JonDoFox settings. There, in the Temporary E-mails tab you may even deactivate the whole feature:

Temporary E-mail addresses -- settings

Protecting search queries at your workplace

In order to mitigate the risk that an outsider might get to know the queries entered into the browser's searchbar, JonDoFox erases them just after they were submitted. Furthermore, the search history gets deleted every thirty minutes. By this means it can on the one hand not happen anymore that the last search query is visible to everyone having access to the user's browser session. On the other hand JonDoFox minimizes the possibility that entries in the search history may compromise the user without loosing the search history feature completely.


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Stable Version

Beta Version


Status of available AN.ON services and information about them.

Aktuell / News

Restrictions for the Dresden (JAP) anonymisation servers
After careful consideration we have decided to restrict the size of downloads over the Dresden (JAP) mixes a little. The reason is to allow a more fair use of scarce resources of our servers especially for users who simply want to surf the Web. more...