The SSL VPN client

The remote client connects to the SSL VPN tunnel in various ways, depending on the VPN configuration.

Tunnel mode establishes a connection to the remote protected network that any application can use. If the client computer runs Microsoft Windows, they can download the tunnel mode client from the web portal.
If the client computer runs Linux or Mac OS X, the user needs to download the tunnel mode client application from the Fortinet Support web site. See the Release Notes for your FortiOS firmware for the specific operating system versions that are supported.

The SSL VPN standalone client installer for Windows is no longer supported in FortiOS 5.4. Users should use the FortiClient installer with the "VPN Only" option instead.