You can let all communications between the mobile user devices and Cortado Server run through a proxy server. You will need the Cortado Proxy Extension for this. Proxy Extension is the DMZ component of Cortado Server. Mobile devices (Smartphones, Tablets) are connected to a proxy server, rather than to the Cortado server. And then the proxy server communicates with the Cortado server (and the Cortado server communicates with the mail server).
Although installation of Proxy Extension is optional, it is, nonetheless, a prerequisite for using the Sharing function (Virtual Data Rooms).
Note! Install the Cortado Proxy Extension before you proceed with the Cortado Server configuration.