Citrix Access Suite 4 for Windows Server 2003: The Official Guide, Third Edition

2017-07-07 02:10:07

Although troubleshooting any distributed system can be challenging and time-consuming , applying a structured methodology to troubleshooting can help sort through possible causes and reveal the root cause of most problems.

This section includes troubleshooting procedures for some of the more common problems found in a Presentation Server environment.

Connections

One of the most common problems in the Presentation Server environment that requires troubleshooting involves connectivity. When users cannot connect to the Presentation Server servers, there are numerous possibilities to consider.

– The ICA client is not configured properly This is often the problem if only one user cannot connect to the farm. If the user is using Program Neighborhood, check the server location address by selecting the connection, right-clicking, and selecting the Properties option. The proper server location address should be entered in the Address List box by clicking the Add button. Note that if TCP/ IP + HTTP is used, the appropriate XML port must be entered when adding the server location. If the Program Neighborhood Agent is being used, make sure the Web Interface URL is correct.

– The Presentation Server server is not accepting any more connections Check to make sure logons have not been disabled by launching the MC, highlighting the server(s) in question, right-clicking, and selecting Properties. Next, click the MetaFrame Settings option and make sure in the Control Options section that the Enable Logons To This Server check box is selected.

– The Presentation Server server's load level is too high If the load level of a server is too high, new sessions will not be directed to the server. Check the load on the server from within the MC. Highlight the server(s) in question and click the Load Manager Monitor tab. If the server is reporting a full load, check the Load Evaluators to make sure they are appropriate. This can also be checked by running qfarm/load from a command prompt. A server at maximum load will report load as 10000.

– The listeners are down Listeners (both ICA and RDP) are the control mechanism by which new sessions are established to Presentation Server servers. The state of the listeners can be checked from the MC. Click the server(s) in question and select the Sessions tab. The listeners for both ICA (ICA-tcp) and RDP (RDP-Tcp) will be shown and should be in a listen state. If either is in a down state, new connections cannot be established to the server, and the listener should be reset by right-clicking the listener and selecting Reset. If this does not bring the listener back to a listen state, reboot the Presentation Server server. Also verify that nothing else is using port 1494. A common way to check connectivity to the Presentation Server server is to run the following from a command prompt:

telnet <insert server name> 1494
The response should be ppICAppICAppICA, which is an ICA banner from the Citrix server. This output will continue until the Telnet session is broken or times out. If this does not appear, there may be a problem with the listeners.

– There are not enough idle sessions available By default, there are two idle sessions available for logons. If more than two connections are made before one of the idle sessions frees up, an error is received on the client when trying to connect. Typically, if the user attempts to connect again, they will be able to log on. If errors of this nature occur during peak login times, increase the number of idle sessions by editing the following Registry key: HKLM\System\ CurrentControlSet\Control\Terminal Server\IdleWinStationPoolCount.

– There are network issues present This could be on the server or client side of the network. The main items to verify include: are the server's network cards functioning properly; are routers and switches between the client and server configured correctly; are firewall settings blocking ICA traffic; and are client network cards configured and functioning properly. As mentioned earlier, one of the best ways to establish connectivity to the Presentation Server server is to run the following from a command prompt:

telnet <insert server name> 1494
The response should be ppICAppICAppICA, which is an ICA banner from the Presentation Server. If this does not appear and the ICA listener is up and running, then something is blocking communication from the client to the server.

– Core services not functional At a minimum, both the Independent Management Architecture (IMA) and Citrix XML services must be running for a Presentation Server server to function properly. Check both of these service states by selecting Control Panel Administrative Tools Services to ensure they are both in a Started state. If their status shows blank, right-click the service and select the Start option.

Shadowing Users

Many end-user problems can be resolved without physically visiting the user by utilizing the shadowing technology included with Presentation Server. Permissions for shadowing are best set up in a Citrix policy and only granted to administrators and managers within the company. Shadowing rights enable the control of a user session to instruct the user on how to perform a certain function, troubleshoot client-side problems, or promote general education about applications, printing, and system orientation. There are a couple of ways to initiate shadowing. One can be started from within the MC by right-clicking the user sessions to be shadowed and selecting the Shadow option. Another method is to use the Shadow taskbar found on the ICA Administrator toolbar. A popular way to give managers access to shadowing without giving them permissions to the MC is to publish the Shadow Taskbar program as a published application.

Troubleshooting the SQL Data Store

If you are using a SQL data store, several troubleshooting tips can assist you in discovering and fixing connectivity problems. The following list consolidates the most common problems encountered with the SQL data store and how to correct the issues.

– The wrong credentials are supplied for SQL authentication During the configuration of a SQL data store, a username and password are entered that are used for accessing the data store database. If this username or password is changed without updating the DSN used to connect to the data store, connectivity problems will be encountered.

– The DSN is configured for NT authentication, not SQL authentication Ensure that the DSN file is configured for the proper method of authentication by opening the Data Sources (ODBC) from within Control Panel Administrative Tools.

– The network connection between the SQL server and the Presentation Server is down Test connectivity by using Data Sources (ODBC) utility from within Control Panel Administrative Tools by selecting the DSN and clicking the Configure button.

– Log space Ensure you have the Truncate Log At Checkpoint option selected or have adequate backups scheduled to ensure that the logs do not grow unnecessarily.

– Worker threads In larger farms (greater than 256 servers), the number of worker threads needs to be increased for proper operation. This can be achieved by using the SQL Server Enterprise Manager, right-clicking the server name, selecting properties, and then clicking the Processor tab and changing the Maximum worker thread count from 256 to a number greater than the number of servers in the farm.

Troubleshooting IMA

The IMA service and underlying subsystems are the core of Presentation Server and must be running on all farm servers for proper operation. The following list consolidates the most common problems encountered with the IMA service and how to correct the issues.

– If an error is received after booting a Presentation Server that states one of more services failed to start, and the nonstarting service is the IMA service, allow the service more time to start, since the initial load on the IMA service will cause delays past the default six-minute time-out of the service manager.

– If a direct connection to the DS is being used, verify that ODBC connectivity exists.

– If the Local Host Cache (LHC) (imalhc.mdb) is missing, corrupt, or provides incorrect information, start by refreshing the LHC and then move on to recreate the LHC. To refresh the LHC, run the following from a command prompt: dsmaint refreshlhc . If this fails, re-create the LHC with the following command: dsmaint recreatelhc .

– Review the event viewer logs for any errors, and research the Citrix Knowledge Center (http://www.support.citrix.com), or contact your local Citrix reseller to assist in troubleshooting.

If the ODBC Connection Fails

If using direct mode connections to the DS, ODBC connectivity is required for proper operation of the IMA service. If ODBC issues are suspected, try the following:

– Verify the name of the DSN file the IMA service is using by looking in the Registry setting HKEY_LOCAL_MACHINE\SOFTWARE\Citrix\IMA\DataSource-Name.

– Reinstall the latest compatible version of MDAC to verify that the correct ODBC files are installed.

– Enable ODBC tracing for further troubleshooting.