Insecure Client-initiated Renegotiation error on TMG

Daniel Davies | 27th February 2014 | Azure

When running an SSLLABS SSL Server Test against a site that is published on TMG you may get the following error “Insecure Client-initiated Renegotiation – Supported INSECURE”

 

To resolve this error on TMG do the following:

  • Ensure KB980346 is installed on your TMG server
    • If not install it via Windows Update
  • You can disable Insecure Renegotiation by adjusting the following registry key
    • Navigate to “HKEY_LOCAL_MACHINESystemCurrentControlSetControlSecurityProvidersSCHANNEL” in REGEDIT
    • Create the following DWORD “AllowInsecureRenegoClients” with a value of 0

  • Restart server

 

Now if you run the SSLLABS check all is good J

About the author

Daniel Davies