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How can i add this SSL chiper suite to firefox? "security.ssl3.rsa.rc4_40_md5"

TurboC
TurboC
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i want to connect to my FortiGate Firewall Virtual Machine via HTTPS, but when i try to do this, Firefox tell me: "Advanced info: SSL_ERROR_NO_CYPHER_OVERLAP". on the FortiGate ufficial site i found this:

If you do not see the login page due to an SSL cipher error during the connection, and you are connecting to the trial license of FortiWeb-VM or a LENC version of FortiWeb, then your browser must be configured to accept encryption of 64-bit strength or less during the handshake. (RC2, RC4, and DES with less than 64-bit strength is supported. AES and 3DES is not supported in these versions.)

For example, in Mozilla Firefox, if you receive this error message:

ssl_error_no_cypher_overlap

you may need to enter about:config in the URL bar, then set security.ssl3.rsa.rc4_40_md5 to true.


http://help.fortinet.com/fweb/541/Content/FortiWeb/fortiweb-admin/connecting_gui_cli.htm


in "about:config" page, i don't see the SSL suite chiper "security.ssl3.rsa.rc4_40_md5". where can i download it? and how can i enable it? my browser version is 46.0 and my operating system is Linux Mint. can you help me to solve this problem? thanks.

i want to connect to my FortiGate Firewall Virtual Machine via HTTPS, but when i try to do this, Firefox tell me: "Advanced info: SSL_ERROR_NO_CYPHER_OVERLAP". on the FortiGate ufficial site i found this: --------------------------------------------------------------------------------------------- If you do not see the login page due to an SSL cipher error during the connection, and you are connecting to the trial license of FortiWeb-VM or a LENC version of FortiWeb, then your browser must be configured to accept encryption of 64-bit strength or less during the handshake. (RC2, RC4, and DES with less than 64-bit strength is supported. AES and 3DES is not supported in these versions.) For example, in Mozilla Firefox, if you receive this error message: ssl_error_no_cypher_overlap you may need to enter about:config in the URL bar, then set security.ssl3.rsa.rc4_40_md5 to true. http://help.fortinet.com/fweb/541/Content/FortiWeb/fortiweb-admin/connecting_gui_cli.htm --------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------- in "about:config" page, i don't see the SSL suite chiper "security.ssl3.rsa.rc4_40_md5". where can i download it? and how can i enable it? my browser version is 46.0 and my operating system is Linux Mint. can you help me to solve this problem? thanks.

All Replies (1)

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 25 Contributor
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I don't think you can add ciphers to Firefox that have "aged out" over the years as they were discovered to be insecure.

Any chance Fortigate has a firmware update??

Do any other browsers work??

In relation to other devices that browsers no longer can connect to, I've seen a suggestion to use a reverse proxy which presents a modern cipher to Firefox but works with the device using an older cipher (no idea on the details). https://www.reddit.com/r/firefox/comments/3coba7/firefox_39_completely_breaks_older_sslv3_pages/csxjtvb