Citrix Interview Questions- 1

      Tell me about yourself?

          My name is XYZ. I am from Bangalore. I have completed my Engineering in computer science Background. I have total 5+ years of experience in IT industry. Currently I am working in ABC as a Citrix administrator as a L2 level.

   Tell me about your company infrastructure?

·         In My Company we have total 75 Xenapp servers in two different farms.

·         In Farm one we have 45 Xenapp6.5 servers and in farm two 30 Xenapp5.0 serves.

·         All the Xenapp servers are hosted in virtual infrastructure.

·         We are using ESX4.0 hypervisor.

·         We use Wyse and HP T610 model thin clients.

·         Most of the users uses server desktop as a HSD solution.

·         We are using Dell M610 blade servers.

·         In backend we have SAN FC storage, EMC Clarion CX400.

·         We have dedicated licensing server, and dedicated two web interface servers configured for network load balancing.

·         We have dedicated database server, and data store with XML.

·         Users login from various branches. We have 27+ branches across the world. We have dedicated site to site VPN.

·         Some of the user’s access this infrastructure through internet, but more than 90% users can use with in the infrastructure only.

    Tell me 10 day to day activities you do in Citrix?

·         Verifying the daily check list.

·         Login in to all Xenapp servers and check all servers can able to login by using test credentials.

·         Checks all published applications are launched properly or not.

·         Sending daily reports to the manager by using Edge Sight.

·         Handling the tickets, resolve the problems based on priority.

·         Taking care of HotFixes, Rollup Packs, and testing applications.

·         Configuring policies based on customer requirements.

·         Updating and configuring licensing server.

·         Adding additional servers in to the farm.

·         Troubleshooting the problems.

      Tell me about your job profile?

          My job profile is managing Xenapp servers in the farms. Troubleshooting the issues. Installing Hot fixes, Rollup Packs. Applying policies based on customer requirements. Adding additional servers in to the farm based on requirement.Installing new applications, checking installed applications are properly launched or not.Updating licensing server, sending daily reports to the manager by using Edge Sight.

     Tell me some common problems you have faced?

1. IMA service is not responding.
2. Users not able to login to the Xenapp servers.
3. Users not able to launch the published applications.
4. Application performance is slow.
5. User unable to find local printers.
6. User got an error no more sessions are allowed.
7. User unable to view any applications.
8. Getting an error like user page can’t be displayed.
9. User tries to launch a published application but it disappears.
10. . User gets an error Invalid username or password even though they give correct credentials. 

         What is the biggest problem you have faced?

IMA service is not starting in services.msc

      

       If the new users are not able to launch published application, what troubleshoot you do?

What can cause applications not to launch through the Citrix Web Interface? 

     Let’s take a look at a few possible causes…

    Citrix Secure Gateway (or) Net Scalar in the way. May be a firewall problem.

• Check weather problem exist for both internal and external users.

• If applications are working with only External users (From the internet) then there is no problem with Citrix Secure Gateway (or) Net Scaler.

• If applications are working with Internal users (In the Network) only

• I.e. External users are unable to launch the application that means we are dealing with following a CSG or Netscaler issue.

• Make sure that the CSG passes its internal diagnostic tests, and make sure the Netscaler has a valid route through to the Web Interface and each Xenapp server in the farm. 

• Make sure that the STA (Secure Ticket Authority) servers used on the Netscaler match exactly the STA servers specified on the Web Interface.

 2. Licensing issues.

If any XenApp server shows 20000 when you using qfarm/load, server experiencing licensing problem.

3.  XML issues.

• If you are having problems with XML, chances are you’ll see some XML errors in the event viewer on either the Web Interface or the farm XML broker.

• Make sure that the port you are using for XML is open between the Web Interface and the farm.

• You can test this from the command line by doing a                                  

o “Telnet <xmlbrokerserver> #”, 

• Using the server name and xml port # from your farm. 

• If it connects and gives you a blank black screen, then traffic is flowing properly.  If it hangs on a blinking cursor, then you should check your firewall settings.

• If XML traffic is OK, your next step should be to re-register the XML service on the XML broker.  Use the command syntax below:

• CTXXMLSS [switches] [/Rnnnn] [/Knnn] [/U] [/?]

• Parameters:

• /Rnnnn – Registers the service on port number nnnn

/Knnn – Keep-Alive nnn seconds (default 9).

/U – Unregisters the service.

/? (help) – Displays the syntax for the utility and information about the utilities options.

4. Corrupted LHC:

• We can recreate LHC by using the following command 

o dsmaint recreatelhc

• It deletes the old “imalhc.mdb” file and recreates empty “imalhc.mdb” file. After creating we’ve to start the IMA services.

• To stop/start IMA services 

o net stop imaservice

o net start imaservice

   5. Data Store corruption:

Go for dscheck  /?  From the command prompt and see all the options

  If the user gets is unable to view any application, what troubleshoot you do?

   Open web interface management console-

   managed published resources plug-in       

    check it is dual mode(or) on-line (or) off-line

          If it is off-line change status to on-line (or) dual

If the application performance is bad, what troubleshoot you do?

Steps to follow if application performance is bad.

1.      Find application performance is bad for single user or multiple users.

2.      If problem is for one user may be network issue or user system performance is slow. So, open task manager of user system and troubleshoot it.

3.      If problem is for multiple users check in which server the users are connect.

4.      For finding which server users connect open App Center -> Farm -> Applications  ->  users tab.

5.      If all problem users are connect with one server prohibit that server

6.      Then you login to that problem server and check cpu and memory utilization by using task manager, kill unnecessary things otherwise reboot that server.

 If user page cannot display, what troubleshoot you do?

Reasons for user page cannot display;

1.      The SSL client certificate is not installed on the user’s workstation browser.

2.      The root certificate of the certificate authority server that issued the client certificate is not uploaded on the Citrix Access Gateway Standard Edition.

Troubleshooting:

1.      From the client workstation

è Import a user certificate

Ex: using IE8 browser, you can import the SSL client certificate under Internet Options > Content > certificates > Personal tab

      Using Firefox browser3.5x or 3.6x you can import the SSL client certificate under tools > Advanced > Encryption > view certificates > your certificates tab.

2.      From the Citrix Access Gateway4.6x appliance

è  Open the Citrix Access Gateway Administration Tool > select the Administration tab > click on Manage under Manage trusted root certificates.

è Upload the root certificate for the certificate authority that issued the client certificate

è Reboot the Citrix Access Gateway appliance

 If the user is unable to find his printer, what troubleshoot you do?

 The user cannot find the local printer in the list of available printers.

Disconnect from citrix, set the local printer to be the default printer, confirm that the Native Clients is the selected citrix client under Advance options, and reconnect to citrix. If the printer is still missing, uninstall and reinstall the citrix client.

 If user get an error no more sessions allowed, what troubleshoot you do?

                Reasons for no more sessions allowed

1.      Session limit policy was applied on policies

2.      Load throttling value in load evaluator may be one impact

Troubleshoot:

1.      Change the session limit policy value in policies

2.      Apply custom load evaluator.

When user launches a published application it disappears from launching, what troubleshoot you do?

On a single PC, I can log in with my account and the application launches fine. I log in with the trouble user and it appears to launch, but then closes and no activity afterwards. The application is only published on one server (currenty on a test server) I've done the following to troubleshoot:

1. Logged into external PC, IE session with same two accounts above and problem persists.

2. Logged into internal PC, IE session with same two accounts above and problem persists. (Tells me it's not the client PC or the Citrix plug-ins.) Even tried different OS with same results.

3. Removed trouble user profile from Citrix server and redirected shares, problem persists. (tells me it shouldn't be the user profile.)

4. Logged directly into server as user and was able to launch application successfully. (tells me it's not the application or user permissions.)

5. Other users of the application are able to launch it without problems through IE sessions or Receiver. (tells me it's not the application)

6. The application does have licensing to it, but when I've tried to run the app as the trouble user, there have been fewer running instances than at other times. (tells me that it's not an application license limitation)

7. User claims that it was working a couple of weeks ago and no changes have been made to the server in that time.

8. I've watched the Citrix Console while the user tried to launch the application. User session appears while connecting, then disappears as the attempt on the client also disappears.

9. Tried the registry changes found in another thread with no changes to problem.

             It is just this single application for this specific user, regardless of where she logs in from. All of her other applications launch OK.

 Difference between ICA & RDP?

                                ICA (1494)                                                            RDP (3389)

Any  OS, Any Device, Any Network.	NO
High Security-by using Encryption and Net Scalar access gateway.	NO
High Definition user experience remotely by using HDX. It supports 3D images, graphics, live web came.	NO
It provides excellent monitoring, reporting, and troubleshooting features by using Edge sight.	NO
It has granule level of control by using citrix policies.	NO
ICA uses multiple virtual channels.	NO
High Performance.	NO
It has better compression by using Branch repeater.	NO
Session Reliability is available	NO

   What is the difference between XenApp5 & 6?    

XenApp 5 Versus XenApp 6 – Key Incompatibilities and Architectural Differences

Data Store:

1. Core data store changes make mixed farms incompatible because of the differences in the structure of and communications to a XenApp 6 and XenApp 5 data store. Consequently, mixed farms will most likely cause data store corruption.

2. XenApp 6.0 is not capable of contacting an IBM DB2 or Access database.

Management Consoles:

1. The new MMC 3.0 Delivery Services Console only works with XenApp 6.0 and is a requirement – it does not work with XenApp 5.0, nor does the 5.0 console work with XenApp 6.0.

2. The XenApp Advanced configuration does not work on a XenApp 6.0 system.

Management and Configuration:

1. Management and configuration infrastructure is policy-based for XenApp 6.0 and XenApp 5.0 and is not compatible with this and makes mixed communication impossible.

2. Worker Groups are specific to XenApp 6.0 and this is a fundamental management change - making mixed farms a problem.

3. Active Directory integration and management is not possible with XenApp 5.0 in a way that XenApp 6.0 allows, so management infrastructure could become massively complex in a mixed environment.

User Experience Consistency:

In a mixed environment with load balancing, configured users would get totally inconsistent options and experiences depending on whether they are connected to a XenApp 5.0 server one day and a XenApp 6.0 server the next.

License Server:

1. Version 11.6.1 Build 9020 onwards is required for XenApp 6.0.

2. Port options on the License Server and files have been removed as of license server 11.5 onwards – so management again would become ambiguous.

Operating System:

Windows Server 2008 R2 is required for XenApp 6.0 and is 64-bit only as is XenApp 6.0, so upgrading from any 32-bit operating system is not possible. XenApp 6 was specifically developed to operate on the 64-bit Windows Server 2008 R2 platform.