By default, the installation process requires an Internet connection to enable installing dependency packages and for synchronizing the operating system clock against an NTP server (for additional details, refer to Synchronizing node clocks.
If you install Redis Enterprise Software (RS) on a machine with no Internet connection, you need to perform these two tasks manually, as follows:
First, you need to install the required dependency packages. When RS is installed on a machine that is not connected to the Internet, the installation process fails and displays an error message informing you it failed to automatically install dependencies. Review the installation steps in the console to see which missing dependencies the process attempted to install. Install all these dependency packages and then run the installation again.
At the end of the installation, the process asks you whether you would like to setup NTP time synchronization. If you choose "Yes" while you are not connected to the Internet, the action fails and displays the appropriate error message, but the installation completes successfully. Despite the successful completion of the installation, you still have to configure all nodes for NTP time synchronization as described in Synchronizing node clocks.