As of PRTG 20.3.60, PRTG provides the option to force the "secure" flag for HTTP cookies. The corresponding registry key option allows you to do this. It is not mandatory, however, if you do not configure the registry hack, cookies will not have the "secure" flag set. Forcing the flag is especially necessary if you use SSL offloading.
Important: If you enable this registry hack, clients that reach the PRTG web server without HTTPS, either directly or behind the load balancer, will not be able to stay logged in to PRTG because the authentication cookie will not work.
Steps to take
Caution: Back up your system before you manipulate the Windows registry!
Open the registry editor and navigate to the following key:
On a 64-bit Windows system, navigate to HKEY_LOCAL_MACHINE\Software\Wow6432Node\Paessler\PRTG Network Monitor\Server\Webserver
On a 32-bit Windows version, navigate to
HKEY_LOCAL_MACHINE\SOFTWARE\Paessler\PRTG Network Monitor\Server\Webserver
Create a new DWORD value:
In the current path, right-click to open the context menu.
Select New | DWORD.
Name the new value forceCookiesSecure.
Set the value of forceCookiesSecure:
Right-click forceCookiesSecure .
Under Value data, enter 1.
Confirm with OK.
Restart the PRTG core server to activate the settings.
PRTG now forces the "secure" flag for HTTP cookies.
Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.