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Handbook

SSL VPN modes of operation

6.0.0
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When a remote client connects to the FortiGate unit, the FortiGate unit authenticates the user based on username, password, and authentication domain. A successful login determines the access rights of remote users according to user group. The user group settings specify whether the connection will operate in web-only mode or tunnel mode.

Web-only mode

Web-only mode provides remote users with a fast and efficient way to access server applications from any thin client computer equipped with a web browser. Web-only mode offers true clientless network access using any web browser that has built-in SSL encryption and the Sun Java Runtime Environment (note that there is no minimum Java/JRE version requirement—any version of Java/JRE currently supported by the supplier of the Java/JRE for the operating system should work).

Support for SSL VPN web-only mode is built into FortiOS. The feature comprises of an SSL daemon running on the FortiGate unit, and a web portal, which provides users with access to network services and resources including HTTP/HTTPS, Telnet, FTP, SMB/CIFS, VNC, RDP, and SSH.

In web-only mode, the FortiGate unit acts as a secure HTML5 HTTPS gateway and authenticates remote users as members of a user group. After successful authentication, the FortiGate unit redirects the web browser to the web portal home page and the user can access the server applications behind the FortiGate unit.

When a user starts a connection to a server from the web portal, FortiOS starts the appropriate client application to communicate with the server. All connections to server applications are new connections from the FortiGate to the server. Communication between the FortiGate and the user continues to be over HTML5 HTTPS, so all user communication with the sever is secured by FortiOS. This includes all supported server protocols (HTTP/HTTPS, Telnet, FTP, SMB/CIFS, VNC, RDP, and SSH).

When the FortiGate unit provides services in web-only mode, a secure connection between the remote client and the FortiGate unit is established through the SSL VPN security in the FortiGate unit and the SSL security in the web browser.

FortiGate SSL VPN web portals have a 1- or 2-column page layout and portal functionality is provided through small applets called widgets. Widget windows can be moved or minimized. The controls within each widget depend on its function. There are predefined web portals and the administrator can create additional portals.

Configuring the FortiGate unit involves selecting the appropriate web portal configuration in the user group settings. These configuration settings determine which server applications can be accessed. SSL encryption is used to ensure traffic confidentiality.

See the FortiOS release notes for information about the operating systems and web browsers supported by SSL VPN web-only mode.

Tunnel mode

In Tunnel mode, remote clients connect to a FortiGate unit that acts as a secure HTTP/HTTPS gateway and authenticates remote users as members of a user group.

The SSL VPN client encrypts all traffic from the remote client computer and sends it to the FortiGate unit through an SSL VPN tunnel over the HTTPS link between the user and the FortiGate unit. Another option is split tunneling, which ensures that only the traffic for the private network is sent to the SSL VPN gateway. Internet traffic is sent through the usual unencrypted route. This conserves bandwidth and alleviates bottlenecks.

When the user initiates a VPN connection with the FortiGate unit through the SSL VPN client, the FortiGate unit establishes a tunnel with the client and assigns the client a virtual IP address from a range of reserved addresses. The client uses the assigned IP address as its source address for the duration of the connection. After the tunnel has been established, the user can access the network behind the FortiGate unit.

When a remote client connects to the FortiGate unit, the FortiGate unit authenticates the user based on username, password, and authentication domain. A successful login determines the access rights of remote users according to user group. The user group settings specify whether the connection will operate in web-only mode or tunnel mode.

Web-only mode

Web-only mode provides remote users with a fast and efficient way to access server applications from any thin client computer equipped with a web browser. Web-only mode offers true clientless network access using any web browser that has built-in SSL encryption and the Sun Java Runtime Environment (note that there is no minimum Java/JRE version requirement—any version of Java/JRE currently supported by the supplier of the Java/JRE for the operating system should work).

Support for SSL VPN web-only mode is built into FortiOS. The feature comprises of an SSL daemon running on the FortiGate unit, and a web portal, which provides users with access to network services and resources including HTTP/HTTPS, Telnet, FTP, SMB/CIFS, VNC, RDP, and SSH.

In web-only mode, the FortiGate unit acts as a secure HTML5 HTTPS gateway and authenticates remote users as members of a user group. After successful authentication, the FortiGate unit redirects the web browser to the web portal home page and the user can access the server applications behind the FortiGate unit.

When a user starts a connection to a server from the web portal, FortiOS starts the appropriate client application to communicate with the server. All connections to server applications are new connections from the FortiGate to the server. Communication between the FortiGate and the user continues to be over HTML5 HTTPS, so all user communication with the sever is secured by FortiOS. This includes all supported server protocols (HTTP/HTTPS, Telnet, FTP, SMB/CIFS, VNC, RDP, and SSH).

When the FortiGate unit provides services in web-only mode, a secure connection between the remote client and the FortiGate unit is established through the SSL VPN security in the FortiGate unit and the SSL security in the web browser.

FortiGate SSL VPN web portals have a 1- or 2-column page layout and portal functionality is provided through small applets called widgets. Widget windows can be moved or minimized. The controls within each widget depend on its function. There are predefined web portals and the administrator can create additional portals.

Configuring the FortiGate unit involves selecting the appropriate web portal configuration in the user group settings. These configuration settings determine which server applications can be accessed. SSL encryption is used to ensure traffic confidentiality.

See the FortiOS release notes for information about the operating systems and web browsers supported by SSL VPN web-only mode.

Tunnel mode

In Tunnel mode, remote clients connect to a FortiGate unit that acts as a secure HTTP/HTTPS gateway and authenticates remote users as members of a user group.

The SSL VPN client encrypts all traffic from the remote client computer and sends it to the FortiGate unit through an SSL VPN tunnel over the HTTPS link between the user and the FortiGate unit. Another option is split tunneling, which ensures that only the traffic for the private network is sent to the SSL VPN gateway. Internet traffic is sent through the usual unencrypted route. This conserves bandwidth and alleviates bottlenecks.

When the user initiates a VPN connection with the FortiGate unit through the SSL VPN client, the FortiGate unit establishes a tunnel with the client and assigns the client a virtual IP address from a range of reserved addresses. The client uses the assigned IP address as its source address for the duration of the connection. After the tunnel has been established, the user can access the network behind the FortiGate unit.