How to set TLS fallback mode or whitelist in Firefox 38 for servers that are TLS version intolerant

Solution Verified - Updated -


  • How can TLS fallback mode or whitelists be configured in Firefox for servers that are TLS version intolerant?
  • Firefox is not able to connect to some websites with older TLS versions (TLS intolerant server side)
  • Firefox disconnects with incompatible versions of TLS
  • Firefox TLS handshakes do not negotiate for backwards compatibility on TLS intolerant configured webservers
  • Firefox does not retry connections if the initial attempt with TLS 1.2 failed on a TLS intolerant webserver
  • Firefox will only permit the use of the older TLS versions 1.1 and 1.0 if the server uses the TLS handshake protocol to negotiate these versions.
  • Automatic fallback for Firefox 38 is disabled

  • Error when connecting to website:

Secure Connection Failed. The connection to HOSTNAME was interrupted while the page was loading.


  • Firefox 38
  • Red Hat Enterprise Linux 5, 6, 7

Subscriber exclusive content

A Red Hat subscription provides unlimited access to our knowledgebase, tools, and much more.

Current Customers and Partners

Log in for full access

Log In

New to Red Hat?

Learn more about Red Hat subscriptions

Using a Red Hat product through a public cloud?

How to access this content