For an overview on what Live Sessions are, see Reference - Live Sessions.
Before any agent can exchange live data through the Server it first has to be enabled on the Server. By default this feature is disabled for security reasons. To change its configuration, start the Loupe Server Administrator and select the Live Sessions tab.
To assist with firewall configuration there are separate ports used for Agent and Loupe Desktop communication. You can choose to override the default settings and use a different port for either, but they must be separate ports and not conflict with the web server used for the Server. You may have to add firewall exception rules to your server as well as to your network firewall.
If you wish you can use SSL to encrypt the Live Session traffic. This is done using standard SSL certificates. If you select an SSL certificate then it will be used for all Live Session communication and the host name used to connect to the server must match the certificate. To import a certificate, use the IIS Manager to import it like you were using it for the web site.