Product Documentation

Use URL Redirection to launch local applications

Jul 25, 2013

In XenDesktop, hosted desktop sessions use URL redirection to launch Local Access applications. URL redirection makes the application available under more than one URL address. It launches a local browser (based on your browser's URL blacklist) by clicking embedded links within a browser in a desktop session. If you navigate to a URL that is not present in the blacklist, the URL is opened in the desktop session again.

In addition to URL redirection, you can also use File Type Association (FTA) redirection. FTA launches local applications when a file is encountered in the session. If the local app is launched, it must have access to the file to open it. Therefore, you can only open files that reside on network shares or on client drives (using CDM) using local apps.

For example, when opening the file \\client\C:\users\<username>\desktop\hugefile.pdf, if a PDF reader is a local app, then the file opens using that PDF reader. Because the local app can access the file directly, there is no network transfer of the file through ICA to open this file.

Note: These features only work for desktop sessions and do not work for application sessions. The only redirection feature you can use for application sessions is Host-to-client content redirection, which is a type of Server FTA. This FTA redirects certain protocols to the client, such as http, https, rtsp, or mms. For example, if you only open embedded links with http, the links directly open with the client application. There is no URL blacklist or whitelist support.

URL redirection and Local App Access

When Local App Access is enabled for virtual desktops, URLs that are displayed to users as links from locally-running applications, from user-hosted applications, or as shortcuts on the desktop are redirected in one of the following ways:
  • From the user's computer to the hosted desktop
  • From the XenDesktop server to the user's computer
  • Rendered in the environment in which they are launched (not redirected)

URL Redirection provides URL matching functionality and based on a predefined list, the URL is selectively launched on the endpoint or the VDA browser. Use URL redirection for end users with a virtual desktop as their primary work spaces.

To specify the redirection path of content from specific Web sites, configure the URL Whitelist and URL Blacklist on the Delivery Agent. These lists consist of multi-string registry keys that specify the policy for URL redirection as described in Local App Access policy settings.

Although all the URLs can be rendered on the VDA itself, there are some exceptions:

  • Geo/Locale information — Web sites that require locale information, such as msn.com or news.google.com (opens a country specific page based on the Geo). For example, if the VDA is provisioned from a data center in the UK and the client is connecting from India, the user expects to see in.msn.com but instead sees uk.msn.com.
  • Multimedia content — Web sites containing rich media content, when rendered on the client device, give the end users a native experience and also save bandwidth even in high latency networks. Although there is Flash redirection feature, this complements by redirecting sites with other media types such as Silverlight. This is in a very secure environment. That is, the URLs that are approved by the administrator are run on the client while the rest of the URLs are redirected to the VDA.

To enable URL redirection during Receiver installation

By default, URL redirection is disabled on user devices when you install Receiver. You can enable it on the command line during installation. To do so, you must:

  • Have Administrator rights
  • As Administrator, install Receiver for All Users on a machine
    Note: When you install as Administrator, the installation location is C:\Program Files\Citrix\ICA Client. Check the installation location to make sure all users can access Receiver.
  • For deployments using the Receiver Standard package, enter:
    CitrixReceiver.exe ALLOW_CLIENTHOSTEDAPPSURL=1

This installs and registers the necessary browser add-ons, and also enables necessary client lockdown settings for enabling LAA, including the URL redirection feature.

To register browser add-ons on devices running Receiver

The URL redirection feature uses add-ons for Internet Explorer, Google Chrome, and Mozilla Firefox browsers. This feature is installed with Receiver 4.0, and you can also register add-ons using the following commands:
  • Internet Explorer
    <Client_Installation_Folder>\redirector.exe /regIE
  • Firefox
    <Client_Installation_Folder>\redirector.exe /regFF
  • Chrome
    <Client_Installation_Folder>\redirector.exe /regChrome
  • All browsers
    <Client_Installation_Folder>\redirector.exe /regAll

For example, to register IE add-ons on Receiver, enter:

C:\Program Files\Citrix\ICA Client\redirector.exe/regIE
To unregister add-ons
  • Internet Explorer
    <Client_Installation_Folder>\redirector.exe /unregIE
  • Firefox
    <Client_Installation_Folder>\redirector.exe /unregFF
  • Chrome
    <Client_Installation_Folder>\redirector.exe /unregChrome
  • All browsers
    <Client_Installation_Folder>\redirector.exe /unregAll

To register browser add-ons on hosted desktops

Register Add-ons on hosted desktops using the following commands.
  • Internet Explorer
    <VDA_Installation_Folder>\VDARedirector.exe /regIE
  • Firefox
    <VDA_Installation_Folder>\VDARedirector.exe  /regFF
  • Chrome
    <VDA_Installation_Folder>\VDARedirector.exe /regChrome
  • All browsers
    <VDA_Installation_Folder>\VDARedirector.exe /regAll

Examples

Register IE add-ons on Desktop OS VDA (Windows 7 or Windows 8):

C:\Program Files\Citrix\ICAService\VDARedirector.exe /regIE

Register IE add-ons on a Server OS VDA (Windows Server 2008 R2 or Windows Server 2012):

 C:\Program Files (x86)\Citrix\System32\VDARedirector.exe/regIE
To unregister Add-ons on hosted desktops
  • Internet Explorer
    <VDA_Installation_Folder>\VDARedirector.exe /unregIE
  • Firefox
    <VDA_Installation_Folder>\VDARedirector.exe  /unregFF
  • Chrome
    <VDA_Installation_Folder>\VDARedirector.exe /unregChrome
  • All browsers
    <VDA_Installation_Folder>\VDARedirector.exe /unregAl

URL interception across browsers

Description Configuration

By default, Internet Explorer redirects the URL entered. If the URL is not in the blacklist but is redirected to another URL by browser or website, the final URL is not redirected even if it is present in the blacklist.

For URL redirection to work correctly, enable the add-on when prompted by the browser. If the add-ons using internet options or the add-ons in the prompt are disabled, URL redirection does not work correctly.

Firefox add-ons always redirect the URLs.

When an add-on is installed by a user or with an installer, Firefox prompts you to allow/stop the add-on installation in new tab page. You must allow the add-on for the feature to work.

Chrome add-on always redirects the final URL that is navigated and not entered URLs.

The extensions have been installed externally. If you disable the extension, the URL redirection feature does not work in Chrome. If the URL redirection is required in Incognito mode, allow the extension to run in InCongnito mode by selecting this option.