Firefox keeps prompting for Proxy Authentication

I have been facing this for a long time since 3.5. something.  Even after upgrading to 3.6 it continues.  Firefox would keep on asking for proxy authentication even though i had given the id and password and even it remembers.  But it will always ask for the id and password.  Today looked around to find a solution, and i came across this, which seems to working.  No popups for authentication for the past 2 or 3 hours.  go to about:config and search and the following properties.

network.proxy.share_proxy_settings – FALSE
network.automatic-ntlm-auth.allow-proxies – FALSE

You can read the full discussion here


Setting these properties alone does not work.  you have to set one more property.

network.auth.use-sspi – FALSE

These setting works in Flock & Thunderbird 3 also.

6 thoughts on “Firefox keeps prompting for Proxy Authentication

  1. I had a similar issue, but the fix is more basic, and the problem symptoms the same, but the cause different.

    Our company nazi IT people has decided to block twitter and facebook and gmail and the lot. So in Chrome and IE, when trying to access these sites, it would fail, and keep quiet about it, but FF prompts you for user name and password (some super IT guys must have access to these sites). (I added * to my exceptions, and now I don’t get the popup)

    So the solution is to “ignore” proxy for the sites you already know are blocked on your proxy, and now FF won’t prompt you for password anymore.

    1. Reenen,

      ‘IE’ uses windows authentication, and authenticates with proxy server silently behind the scenes. Chrome uses IE’s settings in windows, for proxy settings. Hence the same behavior as IE. But Firefox, tries to do it on its own, that is why it tries to authenticate and find out if you have access to the site.

      But, yeah, for your problem, the best way would be to ignore proxy for the site if you know they are already blocked.

  2. signon.autologin.proxy – no such parameter in FF
    Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv: Gecko/20110803 Firefox/3.6.20 ( .NET CLR 3.5.30729; .NET4.0E)

  3. It’s actually a cool and helpful piece of info. I am happy that you simply shared this useful information with us. Please stay us informed like this. Thank you for sharing.

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