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Present Situation:

  • Configure Firefox to use a proxy server either by direct proxy details or PAC file.
  • When a site is accessed, you get a Login dialog (from FF) for the proxy. We provide credentials and click OK. Additionally we specify Firefox to "Remember" this password.
  • Close browser or reboot computer.


  • The login prompt pops up again but with the user credentials filled in already. So you just need to click OK and will get you connected with Internet.

Ultimate Requirement: This re-challenging needs to be avoided. Once a user authenticates from browser to proxy, the browser should use the stored credentials (only if we directed Firefox to "Remember" the credentials) "automatically" without re-popping the dialog box.

In effect, the user won't know that behind-the-scenes, he was actually being authenticated and only then, was allowed to connect to the Internet. Logically following, if the user credential on squid (or any proxy) is changed, Firefox should pop up the challenge that time only and does not go in an infinite loop of trying to get user to authenticate with previous old credential.

Is there any way to provide credentials to the proxy server via URL or using a PAC file?

share|improve this question

Add this line:

pref("signon.autologin.proxy", true);

to your prefs.js file

share|improve this answer
thanks for the update ! – linuxuser Jul 30 '12 at 10:55
Was this helpful? – VBwhatnow Jul 30 '12 at 13:32
Actually, my requirement was to implement this facility using PAC file. Sorry I should have stressed this properly in my question. But, thanks for your time! – linuxuser Aug 6 '12 at 10:38

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