Product Documentation

Configure Flash Redirection on the user device

Jun 18, 2013
To use Flash Redirection, install Citrix Receiver and the Adobe Flash Player on the user device. No further configuration is required on the user device. However, you can change the default settings using Group Policy Objects as described in this section.

Use Group Policy Objects to configure Flash Redirection on the user device

  1. Create or select an existing Group Policy Object.
  2. Import and add the HDX MediaStream Flash Redirection - Client administrative template (HdxFlash-Client.adm), available in:
    • For 32-bit computers: %Program Files%\Citrix\ICA Client\Configuration\language
    • For 64-bit computers: %Program Files (x86)%\Citrix\ICA Client\Configuration\language

    The policy settings appear under Administrative Templates > Classic Administrative Templates (ADM) > HDX MediaStream Flash Redirection - Client.

    Note: For details on creating Group Policy Objects and importing and adding templates, see the Microsoft Active Directory documentation at http://www.microsoft.com.

Change when Flash Redirection is used

In conjunction with server-side settings, the Enable HDX MediaStream Flash Redirection on the user device policy setting controls whether Adobe Flash content is redirected to the user device for local rendering.
Note: If no configuration is set and Desktop Lock is used, Flash Redirection is enabled on the user device by default.

By default, Flash Redirection is enabled and uses intelligent network detection to determine when to play Flash content on the user device. To change when Flash Redirection is used or to disable Flash Redirection on the user device:

  1. From the Setting list, select Enable HDX MediaStream Flash Redirection on the user device and click policy setting.
  2. Select Not Configured, Enabled (the default), or Disabled.
  3. If you selected Enabled, choose an option from the Use HDX MediaStream Flash Redirection list:
    • To use the latest Flash Redirection functionality when the required configuration is present, and revert to server-side rendering when it is not, select Only with Second Generation.
    • To always use Flash Redirection, select Always. Flash content plays on the user device.
    • To never use Flash Redirection, select Never. Flash content plays on the server.
    • To use intelligent network detection to assess the security level of the client-side network to determine when using Flash Redirection is appropriate, select Ask (the default). If the security of the network cannot be determined, the user is asked whether to use Flash Redirection. If the network security level cannot be determined, the user is prompted to choose whether to use Flash Redirection.

      The following illustration indicates how the Flash Redirection is handled for various network types.


      Intelligent network detection for Flash Redirection
      Note: Users can override intelligent network detection from the Citrix Receiver - Desktop Viewer Preferences dialog box by selecting Optimize or Don't Optimize in the Flash tab. The choices available vary depending on how Flash Redirection is configured on the user device, as shown in the following illustration.

      User control of Flash Redirection

Synchronize client-side HTTP cookies with the server-side

Synchronization of the client-side HTTP cookies with the server-side is disabled by default. Enable synchronization to download HTTP cookies from the server. These HTTP cookies are then used for client-side content fetching and are available as needed by sites containing Flash content.
Note: Client-side cookies are not replaced during the synchronization; they remain available even if the synchronization policy is later disabled.
  1. From the Setting list, select Enable synchronization of the client-side HTTP cookies with the server-side and click policy setting.
  2. Select Not Configured, Enabled, or Disabled (the default).

Enable server-side content fetching

By default, Flash Redirection downloads Adobe Flash content to the user device, where it is played. Enabling server-side content fetching causes the Flash content to download to the server and then be sent to the user device. Unless there is an overriding policy (such as a site blocked through the Flash URL compatibility list policy setting), the Flash content plays on the user device.

Server-side content fetching is frequently used when:
  • The user device connects to internal sites through Citrix NetScaler Gateway.
  • The user device does not have direct access to the Internet.
Note: Server-side content fetching does not support Flash applications using Real Time Messaging Protocols (RTMP). Instead, server-side rendering is used for such sites.
Second generation Flash Redirection supports three enabling options for server-side content fetching, as described in the following table. Two of these options include the ability to cache server-side content on the user device; this improves performance because content that is reused is already available on the user device for rendering.
Note: The contents of this cache are stored separately from other HTTP content cached on the user device.
Option Description
Disabled Disables server-side content fetching, overriding the Flash server-side content fetching URL list setting on the server. Server-side content fetching fallback is also disabled.
Enabled Enables server-side content fetching for web pages and Flash applications identified in the Flash server-side content fetching URL list. Server-side content fetching fallback is available, but Flash content is not cached.
Enabled (persistent caching) Enables server-side content fetching for web pages and Flash applications identified in the Flash server-side content fetching URL list. Server-side content fetching fallback is available. Content obtained through server-side fetching is cached on the user device and stored from session to session.
Enabled (temporary caching) Enables server-side content fetching for web pages and Flash applications identified in the Flash server-side content fetching URL list. Server-side content fetching fallback is available. Content obtained through server-side fetching is cached on the user device and deleted at the end of the session.
Note: With second generation Flash redirection, fallback to server-side content fetching begins automatically when any of the above enabling options is selected and client-side fetching of .swf files fails.

Enabling server-side content fetching requires settings on both the client device and the server:

  1. From the Setting list, select Enable server-side content fetching and click policy setting.
  2. Select Not Configured, Enabled, or Disabled (the default). If you are enabling this setting, choose an option from the Server-side content fetching state list:
    • Disabled
      Note: This setting is preserved in the Registry.
    • Enabled
    • Enabled (persistent caching)
    • Enabled (temporary caching)
  3. On the server, enable the Flash server-side content fetching URL list policy setting and populate it with target URLs.

Redirect user devices to other servers for client-side content fetching

You can redirect an attempt to obtain Flash content using the URL rewriting rules for client-side content fetching setting, which is a second generation Flash Redirection feature. When configuring this feature, you provide two URL patterns using Perl regular expressions. If the user device attempts to fetch content from a website matching the first pattern (the URL match pattern), it is redirected to the website specified by the second pattern (the rewritten URL format).

You can use this setting to compensate for content delivery networks (CDN). Some websites delivering Flash content use CDN redirection to enable the user to obtain the content from the nearest of a group of servers containing the same content. When using the Flash Redirection client-side content fetching feature, the Flash content is requested from the user device, while the rest of the web page on which the Flash content resides is requested by the server. If CDN is in use, the server request is redirected to the closest server, and the user device request follows to the same location. Note that this may not be the location closest to the user device; depending on distance, there could be a noticeable delay between the loading of the web page and the playing of the Flash content.

  1. From the Setting list, select URL rewriting rules for client-side content fetching and click policy setting.
  2. Select Not Configured, Enabled, or Disabled. Not Configured is the default; Disabled causes any URL rewriting rules configured in the next step to be ignored.
  3. If you selected Enabled, click Show. Using Perl regular expression syntax, type the URL match pattern in the Value name box and the rewritten URL format in the Value box.