I use Firefox 44.0.2 on a Linux Xubuntu system. I'm trying to access a company website that requires a certificate.

I can confirm I have the correct certificate in Preferences->Advanced->Certificates->View Certifacates->Your Certificates

It's there and it's the same certificate I successfully use on my Chrome browser on my Windows machine. When I try to access the website from the Windows Chrome, I get a pop up asking me to select one of my certs, I select the correct one and everything works.

My issue is that Firefox on my Linux never prompts me to select a certificate when I try to access the website. I just get a "400 No required SSL certificate was sent."

How can I get Firefox to prompt me for a cert? Or how can I tell him which cert to use?


I have just been experimenting with this myself. It seems that Firefox will only prompt if you have already imported a certificate signed by the same issuer who has signed site's SSL certificate.

So get your CA to sign both the server and client certificates, then import the client certificate into Firefox (via the Preferences window.) The next time you visit the site, Firefox will notice that it has a client certificate signed by the same CA as the server's SSL certificate, so it will prompt you whether to use this or not.

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    Most people/organizations would use a public trusted CA for their main public facing URLs, and a private self-issued certificate for private/admin-related URLs. So that is not an option, and it certainly shouldn't be a requirement. – Craig Hicks Jun 14 '18 at 22:33
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    @CraigHicks: Hey don't shoot the messenger, I'm not a Firefox dev so I didn't make the rules! I just found out through experimentation that this is what it took to make it work. I would've suggested logging an issue for it but Mozilla stopped caring what its users wanted a long time ago so the chances of getting this fixed are basically zero. – Malvineous Jun 17 '18 at 4:26
  • :) Your effort is appreciated! However, I did succeed in loading in a privately created certificate to my Firefox browser following these instructions: knowledge.digicert.com/solution/SO5437.html. This was not a digicert certificate, but one I created myself. – Craig Hicks Jun 17 '18 at 18:47

In my case the web server (nginx) has SPDY enabled. I disabled it and now Firefox works as expected and prompts for certificate.

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