This is a Roundcube webmail plugin that enables Duo Security Two Factor Authentication.
It creates an additional page after successful username/password authentication that requires a 2nd Factor of Authentication using Duo Security (push, sms, call, code).
Same as any other Roundcube plugin. Clone the repository in the plugins directory of your Roundcube installation or download the zip from GitHub and unzip it in that directory.
PLEASE NOTE - If you have downloaded the plugin via the "Download Zip" button in GitHub, rename the extracted folder to "duo_auth"
Enter all keys necessary for integration with Duo in the config.inc.php file. Assuming a Duo integration has already been created in Duo's Admin Panel, you will be able to find all the information requested in the config.inc.php there.