In this article we would discuss various stages involved from typing in Citrix URL till application lunches on user’s machine.
There are three stages involved in this
• Application enumeration
• ICA file creation
• Application launch process
First user launches the web browser and types in URL, it connects to web interface. Web interface returns logon page depending upon the URL entered. User then types credentials in logon page, user credentials are forwarded to web interface which forwards it to XML broker. XML broker service passes it o IMA service either in http or https form. IMA forwards it to local security authority service which is passed to domain controller post encryption. Domain controller in return provides user SID’s and list of group SID’s back to local security authority., which passes it further to IMA. IMA uses these SID’s to search LHC for list of applications and list of group policies for this particular authenticated user. List of application to which user has access to are returned back to web interface which enumerated to users web page using java objects.
Now user has list of applications listed on his screen, user then clicks on one of application to start the launch process. ICA file is created using web interface which is used by Citrix Receiver to connect to application server. When user clicks on application, the information is passed to web interface. Web Interface passes the application information together with the user’s Worker Group Preference policy back to IMA on the XML broker server. IMA service on XML broker machine contacts zone data collector which tries to find out a least loaded server according to the Worker Group preference list. Zone data collector queries Citrix Service Manager of that server to verify whether the server has the required application installed. If yes, it provides this server’s host ID to the XML broker. XML broker check for IP address using LHC which is passed to web interface. Web interface creates ICA file which is transferred to user.
Citrix receiver uses the ICA file to launch an ICA connection to the least loaded XenApp server. The XenApp server launches the application for the user.