====== Shadowing a Device Using Reverse VNC ======
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**Xcalibur W** offers //shadowing//, enabling the system administrator to take control of any enrolled device using VNC as the underlying protocol. The service is self-managing, allowing one-click usage. **Xcalibur W** uses HTLM5 for the rendering of the remote session, therefore administrator is required to use an HTLM5 webbrowser. 

===== How It Works =====
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**Xcalibur W** features a //VNC Proxy// that acts as a gateway between the administrator console and the device being managed. As shown below, the VNC session is actually two separate VNC connections:

  * one reverse-VNC connection, from the device to **Xcalibur W** Server; and
  * one direct-VNC connection, from the administrator console to **Xcalibur W** Agent

{{ :advanced:shadowing_a_device_using_reverse_vnc.png }}

The port numbers for the outbound VNC connections to the **Xcalibur W** Server can be customized as below.

===== Initiating the VNC session =====
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Right-click a device in the Device List and select **Remote desktop (VNC)** from the  [[:installation_guide:first_time_use:main_device_list#context_menu|Contextual Menu]].

{{ advanced:chippc_vnc1.png }}

A task is published to the selected device, requesting it to initiate a reverse VNC session to the **Xcalibur W** proxy VNC server. The device will pick up the published task and then process it. Once complete, a dialog box - **Available VNC sessions** - appears, indicating that the device is ready to be shadowed.
 
{{ advanced:chippc_vnc2.png }}

From the **Available VNC sessions** window, the administrator can start a remote assistance session, end a session, or start a view-only session, as shown below.

{{ advanced:vnc_window.png }}

Click on the VNC connection to open a new browser window (using **HTLM5**) to shadow the selected device.

{{ advanced:chippc_vnc3.png }}

|{{:tip.png |}} Note that even if you close the VNC window, the reverse VNC connection will remain active on the server, potentially allowing other **Xcalibur W** users to access it. To close the reverse VNC connection, use the {{:advanced:delete.png|}} button in the **Available VNC connections** dialog box.|

===== Advanced Settings =====
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Configure VNC-related settings on the //Settings// page (**Views > Manager Options > Settings**).

{{ advanced:vnc4.png }}

**VNC Proxy Automatic Close**

Sets the delay after which the proxy will close all active VNC connections on the server.

**Range of Ports - HTLM5 Viewers**

Defines the range of ports used for the TCP outbound connections from the Administrator Console to the **Xcalibur W** Server.

**Range of Ports - Agents Connections**

Defines the range of ports used for the TCP outbound connection from the remote device to the **Xcalibur W** Server.

**Ensure the following TCP ports are opened** on each device:
^  ^  |
|**Remote Device**|Outbound TCP 5980~5999|
|**Xcalibur W Server**|Inbound TCP 5900~5918 & 5980~5999|