When the cusotmer uses SSL VPN with MS Explorer 11, the USG6370 firewall suggestS to download and install ActiveX for Mozilla. it is incorrect.
Firstly,when you IE11 to access to FW, let customer to check if the proxy server setting is configured, this setting maybe cause the current problem, as following:
But after customer confirmed, there isn't proxy server setting in the IE setting.
And then, let customer to check if the SSL VPN domain (URL) was added to the “ compatibility view setting” in the IE tools, the customer confirmed that it wasn't added. So this is the root cuase.
For the IE11, this IE version has some features are different from the old version, due to the USG6370 SSL-VPN sends the activeX plug-in components will met some problem, and it can’t know the browser is IE, so can’t find the correct plug-in components and install it.
The solution is to add the SSL VPN domain(URL) to the “compatibility view setting” in the IE tools, as following: