Product Documentation

Configuring Citrix Receiver for HTML5

Nov 04, 2016

To enable users to access resources hosted on XenDesktop and XenApp in their browsers, you must create a StoreFront store and enable Citrix Receiver for HTML5. You must also enable WebSocket connections on NetScaler Gateway, XenApp, and XenDesktop, as required. Additionally, you can enhance the user experience by installing optional components on the machines providing the desktops and applications.

To enable direct connections to XenDesktop and XenApp

Citrix Receiver for HTML5 uses the WebSocket protocol to access virtual desktops and hosted applications. By default, WebSocket connections are prohibited on XenDesktop and XenApp. If you plan to enable users to access desktops and applications from the local network without connecting through NetScaler Gateway, you must allow WebSocket connections on XenDesktop and XenApp.

WebSocket connections are also disabled by default on NetScaler Gateway. For remote users accessing their desktops and applications through NetScaler Gateway, you must create an HTTP profile with WebSocket connections enabled and either bind this to the NetScaler Gateway virtual server or apply the profile globally. For more information about creating HTTP profiles, see HTTP Configurations.

Caution: Editing the registry incorrectly can cause serious problems that may require you to reinstall your operating system. Citrix cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk. Be sure to back up the registry before you edit it.

Important: If you are using SecureICA to encrypt communications between users' devices and your XenDesktop or XenApp servers, note that Citrix Receiver for HTML5 supports Basic encryption only.

To enable connections to XenDesktop and XenApp using Provisioning Services

If you plan to deploy provisioned (non-persistent) machines using Provisioning Services, create the machine catalog and delivery group for which you want to enable Citrix Receiver for HTML5 connections. Ensure that the WebSocket policies you configured apply to your machine catalog.

Machines must be restarted to apply the WebSocket policies. For Provisioning Services-based machines configured to use persistent write cache files and machines deployed using MCS (which have separate identity disks), the policies are persisted when the machines restart. However, for Provisioning Services-based machine catalogs configured to use temporary write cache files, these policies must be applied to the vDisk or they will not be implemented successfully on target devices.

Complete the following steps to ensure that the policies are correctly applied to the vDisk.

  1. Using the Provisioning Services console, shut down a target device that is part of the machine catalog and delivery group. Change the access type of the target device from Production to Maintenance.

    For details, see Managing Target Devices. You must use a target device that is part of the machine catalog and delivery group or the policies will not be applied.

  2. Create a new version of your vDisk and leave it with Access set to Maintenance.

    For details, see Manually Updating a vDisk Image.

  3. Start the maintenance target device, selecting the maintenance vDisk version from the boot menu. Verify that the following keys are added to the registry.

    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Citrix\ICAPolicies\AcceptWebSocketsConnections

    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Citrix\WebSocketsPort

    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Citrix\WSTrustedOriginServerList

  4. Shut down the target device, change the target device access type back to Production, and promote the new vDisk version to production. Then, start the target device and restart any other target devices currently running from the existing vDisk.

    If you do not use vDisk versioning, you can apply the policies to your base vDisk image by shutting down all the target devices that use the vDisk, placing the vDisk in Private Image mode, and then starting the target device to update the image.

To configure optional components

Two optional components are available that enhance the experience for Citrix Receiver for HTML5 users by increasing integration with XenDesktop and XenApp.

  • App Switcher enables users to switch between multiple applications running in the same session. When session sharing is enabled on XenApp, which it is by default, applications opened within the same session appear in the same browser tab. App Switcher provides a taskbar running within the session that displays all the applications currently running in the session, enabling users to switch between them.
  • The Citrix PDF Universal Printer driver enables users to print documents opened with hosted applications or applications running on virtual desktops delivered by XenDesktop 7.6 and XenApp 7.6. When a user selects the Citrix PDF Printer option, the driver converts the file to PDF and transfers the PDF to the local device. The PDF is then opened in a new browser tab for viewing and printing from a locally attached printer.
  1. If you plan to enable session sharing on your XenApp deployment, download the App Switcher installer. Ensure that .NET Framework 4.0.3 is installed and enabled, then install App Switcher on each machine providing applications for Citrix Receiver for HTML5 users.

    App Switcher is configured to run automatically in the background when users establish a session.

  2. If you want to enable users to print documents opened with hosted applications or applications running on virtual desktops delivered by XenDesktop 7.6 and XenApp 7.6, complete the following steps.
    1. Download the Citrix PDF Printing Feature Pack and install the Citrix PDF Universal Printer driver on each machine providing desktops or applications for Citrix Receiver for HTML5 users. After installing the printer driver, restart the machine.
    2. In Citrix Studio, select the Policy node in the left pane and either create a new policy or edit an existing policy.

      For more information about configuring XenDesktop and XenApp policies, see Citrix policies.

    3. Set the Auto-create PDF Universal Printer policy setting to Enabled.

To enable Citrix Receiver for HTML5 on StoreFront

You must enable Receiver for HTML5 on the Receiver for Web site for the StoreFront store that provides the desktops and applications you want to make available to Citrix Receiver for HTML5 users.

Important: In multiple-server StoreFront deployments, use only one server at a time to make changes to the configuration of the server group. Ensure that the Citrix StoreFront management console is not running on any of the other servers in the deployment. Once complete, propagate your configuration changes to the server group so that the other servers in the deployment are updated.
  1. If you have not already done so, deploy StoreFront and create a store aggregating the desktops and applications you want to make available to Citrix Receiver for HTML5 users.

    A Receiver for Web site is created automatically for new stores. For more information about creating StoreFront stores, see Create a store.

  2. In the Citrix StoreFront management console, select the Receiver for Web node in the left pane. From the results pane, select the site providing resources for Receiver for HTML5 users and, in the Actions pane, click Deploy Citrix Receiver.
  3. Enable Citrix Receiver for HTML5 by selecting one of the following options.
    • If want users to access desktops and applications from the site using a locally installed version of Citrix Receiver, where available, select Use Receiver for HTML5 if local install fails. Users who already have Citrix Receiver installed cannot use Citrix Receiver for HTML5 to access resources from the site. Windows and Mac OS X users without Citrix Receiver are prompted to install it every time they log on to the site, but can use Citrix Receiver for HTML5 if they are unable to install Citrix Receiver.
    • If you want all users to access desktops and applications from the site through Citrix Receiver for HTML5 regardless of whether they have a locally installed version of Citrix Receiver, select Always use Receiver for HTML5.
  4. If you changed the port used when you allowed WebSocket connections on XenDesktop or XenApp, complete the following steps to change the WebSocket port for the Citrix Receiver for Web site.
    1. Use a text editor to open the web.config file for the Citrix Receiver for Web site, which is typically located in the C:\inetpub\wwwroot\Citrix\storenameWeb directory, where storename is the name specified for the store when it was created.
    2. Locate the following element in the file.
      <html5 ... preferences="" ... />
      
    3. Set the value of the preferences attribute to wsPort:portnumber;, where portnumber is the port that you configured in the policy.

Session Reliability

With Session Reliability, the session remains active on the server. To indicate that connectivity is lost, the user’s display freezes until connectivity resumes on the other side of the tunnel. The user continues to access the display during the interruption and can resume interacting with the application when the network connection is restored. Session Reliability reconnects users without reauthentication prompts.

Note

Citrix Receiver for HTML5 users cannot override the server setting.

You can use Session Reliability with Transport Layer Security (TLS).

Note

TLS encrypts only the data sent between the user device and NetScaler Gateway.

Using Session Reliability policies

The Session Reliability connections policy setting allows or prevents Session Reliability.

The Session Reliability time-out policy setting has a default value of 180 seconds, or three minutes. Though you can extend the amount of time Session Reliability keeps a session open, this feature is designed to be convenient to the user and it does not, therefore, disconnect the session.

Incoming Session Reliability connections use port 2598, unless you change the port number defined in the Session Reliability port number policy setting.

Tip

As you extend the amount of time a session is kept open, chances increase that a user might get distracted and walk away from the user device, potentially leaving the session accessible to unauthorized users.

Configuring Session Reliability

By default, Session Reliability is enabled.

To disable Session Reliability:

  1. Launch Citrix Studio.
  2. Open the Session Reliability connections policy.
  3. Set the policy to Prohibited.
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Configuring Session Reliability time-out

By default, the Session Reliability time-out is set to 180 seconds.

Note: Session Reliability time-out policy can be configured only with XenApp/XenDesktop 7.11 and later.

To modify the Session Reliability time-out:

  1. Launch Citrix Studio.
  2. Open the Session Reliability  time-out policy.
  3. Edit the time-out value.
  4. Click OK.

Configuring Reconnect user interface transparency level

The Session User Interface is displayed during Session Reliability reconnect attempts. The transparency level of the user interface can be modified using a Citrix Studio policy.

By default, the Reconnect user interface transparency is set to 80%.

To modify the Reconnect user interface transparency level:

  1. Launch Citrix Studio.
  2. Open the Reconnect UI transparency level policy.
  3. Edit the value.
  4. Click OK
For XenDesktop Version 7.10 or earlier, use the default.ica file in StoreFront to modify the connection time-out for Session Reliability. By default, this time-out value is set to 180 seconds (or three minutes).

Setting

Example

Default

SessionReliabilityTTL

SessionReliabilityTTL=120

180

How Session Reliability works

When Session Reliability is enabled, consider the following:

  • A session window is grayed out when a reconnection is in progress. Once a session is timed out, it is disconnected.
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Tip

You can alter the grayscale level used for an inactive session using Desktop Studio. By default, this value is set to 80. The maximum value cannot exceed 100 (indicates a transparent window) and the minimum value can be set to 0 (a fully blacked out screen).

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