![\"\"](\"https:\/\/ingmarverheij.com\/wp-content\/uploads\/2012\/07\/Citrix-ICA-icon.png\" "\\"\\""){kind=icon}
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The Citrix Receiver (XenApp plugin \/ Online plugin \/ ICA Client \/ WinFrame client) has a file association<\/a> with the .ICA extension. This means that each time you open a file with the .ICA extension the Citrix Receiver is launched to interpret the file (and act upon the content of the file).<\/p>\n In this article I\u2019ll explain how the .ICA file is constructed, what sections and properties are commonly used and how you can create the file. <\/p>\n <\/p>\n In a nutshell what this protocols does is sending input from the client (like keyboard, mouse, audio, etc.) to the remote system and receive the output (like video, sound, etc.) from the remote system via the network. On the client (a workstation, laptop or thin client) a piece of software is used to handle this traffic. At the moment of this writing the Citrix Receiver<\/a> is used.<\/p>\n Files with the extension .ICA contain information required to connect to the remote system, including session properties and (optionally) authentication.<\/p>\n <\/p>\n Files with an .ICA extension are associated with a Citrix ICA client. This is done via a File Type Association<\/a> (or FTA). <\/p>\n In the shell\\open\\command <\/em>key the default value shows what executable to run when a file with the .ICA file extension is launched. In my case: <\/p>\n <\/p>\n <\/p>\n .ICA files are stored in plain text with ISO\/IEC 8859<\/a> encoding (except for older \u2018legacy\u2019 clients) so they can easily be viewed and edited in a basic text editor. The content is stored in the INI file format<\/a> with a basic structure composed of \u201csections\u201d and \u201cproperties\u201d.<\/p>\n Properties are stored in separate sections, recognizable by the square brackets [ and ]. In a basic ICA file the following three sections are present:<\/p>\n Each section has properties (or settings) assigned, some of there are mandatory but most are optional. In the next sections I\u2019ll explain the most common settings and the not-so-common settings that are available.<\/p>\n <\/p>\n Each section contains a list of properties (or settings) that can be set. I\u2019ll describe the most common settings per section, a larger (not complete) list of properties can be found in the ICA Settings Reference<\/a> on Citrix eDocs.<\/p>\n <\/p>\n This section contains setting(s) that describe how the file is encoded.<\/p>\n In the example the .ICA file is stored in the default encoding, ISO8859_1.<\/p>\nICA \u2013 Independent Computing Architecture<\/font><\/h2>\n
![\"Client-Server](\"https:\/\/ingmarverheij.com\/wp-content\/uploads\/2012\/07\/image_thumb1.png\" "\\"Client-Server")
<\/a>To start at the beginning, ICA stands for Independent Computing Architecture. It is a protocol used in Citrix XenApp<\/a> \/ XenDesktop<\/a> (or previously Presentation Server, MetaFrame, WinFrame) to separate the application logic (which runs on a remote system, usually in a datacenter) and the presentation (on the client).<\/p>\n.ICA File<\/font><\/h2>\n
File Type Association (FTA)<\/font><\/h3>\n
![\"HKEY_CLASSES_ROOT\\.ica\"](\"https:\/\/ingmarverheij.com\/wp-content\/uploads\/2012\/07\/HKCR_ICA_thumb.png\" "\\"HKEY_CLASSES_ROOT\\.ica\\"")
<\/a>In the registry hive HKEY_CLASSES_ROOT <\/strong>a key with the name .ica <\/strong>specifies the name of the file type and the content type. <\/p>\n\n
![\"HKEY_CLASSES_ROOT\\Citrix.ICA.Client.2.7\"](\"https:\/\/ingmarverheij.com\/wp-content\/uploads\/2012\/07\/HKCR_Citrix.ICA_.Client.2.7_thumb.png\" "\\"HKEY_CLASSES_ROOT\\Citrix.ICA.Client.2.7\\"")
<\/a>The name is correlated to the key HKEY_CLASSES_ROOT\\<key name><\/strong> and describes how the file is handled, what icon to show, what items should be visible in context menu etc. <\/p>\n"C:\\Program Files (x86)\\Citrix\\ICA Client\\wfcrun32.exe" "%1"<\/pre>\n
Basic structure<\/h3>\n
[WFClient]\r\n\r\n[ApplicationServers]\r\n\r\n[%ConnectionName%]<\/pre>\n
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Properties per section<\/font><\/h3>\n
[Encoding] (Optional)<\/em><\/font><\/font><\/h6>\n
Example<\/h5>\n
[Encoding]\r\nInputEncoding = ISO8859_1<\/pre>\n
Settings<\/h5>\n
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