What could be the reason why the ZyWALL / USG Series Security Gateways Graphical User Interface (WEB GUI) is not available through the Google Chrome web browser?
When you try to connect to the ZyWALL / USG Series Security Gateways web configurator through the Google Chrome 48 browser as well as browsers that use the Chromium shell (e.g. Opera 35), you may encounter the following error :
This is because Google has banned the use of the RC4 security algorithm for HTTPS connections and the ZyWALL / USG series gateways use this algorithm by default.
There are currently two ways to solve the problem.
1. Disable the redirection from HTTP to HTTPS by entering special commands over an SSH connection:
In this case, you have to need to use the unencrypted HTTP protocol when connecting to the ZyWALL / USG web configurator.
2. Disable the use of non-cryptographic RC4 / DES algorithms in the ZyWALL / USG settings with the following commands:
In this case, the ZyWALL / USG uses the AES algorithm even if the restrictions has not been removed.