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Description This article describes how to configure the SSL-VPN width and height settings in order to have the optimal RDP resolution on users' screens.
Scope FortiOS 7.0.6 and above and 7.2.0 and above
Solution

There are different ways to configure RDP scaling inside FortiOS:

 

1) Under the SSL-VPN web portal:

 

# config vpn ssl web portal

    edit "RDP_Portal"
        set tunnel-mode enable
        set web-mode enable
        set ip-pools "SSLVPN_TUNNEL_ADDR1"
        # config bookmark-group
            edit "gui-bookmarks"
            # config bookmarks
                edit "RDP"
                   set apptype rdp

                   set host "192.168.1.1"
                   set port 3389

                   set width (0-65535, default = 0)
                   set height (0-65535, default = 0)
           next
    end

 

2) Under Personal or User group bookmarks:

 

# conf vpn ssl web [user-group-bookmark | user-bookmark]
    edit "fortinet#"
    # config bookmarks
        edit "RDP-BOOKMARK"
            set apptype rdp
            set host "10.10.10.10"
            set port 3389

            set width (0-65535, default = 0)
            set height (0-65535, default = 0)
        next
    end

 

3) Under the SSL-VPN web portal:

 

    edit "RDP_Portal"
        set tunnel-mode enable
        set web-mode enable
        set ip-pools "SSLVPN_TUNNEL_ADDR1"

        set default-window-width:  0  (default 1024)

        set default-window-height: 0   (default 768)

end

 

It is necessary to have web-mode enabled on the portal to see the 'default-window' settings.

To achieve full screen when using RDP, these settings and the bookmark settings must be set to 0 as explained in scenario 3 which will scale with a full-screen browser window.

 

There are three factors which decide the final outcome of how RDP will scale:

 

1) If width & height settings under bookmark are non zero values, then these values will be used.


2) If width & height settings under bookmark are zero and width/height settings under portal are not zero, then FortiOS will use the setting configured under the portal.


3) If width & height settings are zero under both bookmark and portal, then RDP will auto-scale based on individual users' browser's window size.