Product Documentation

Troubleshooting

If the content switching feature does not work as expected after you have configured it, you can use some common tools to access Citrix ADC resources and diagnose the problem.

Resources for Troubleshooting Content Switching

For best results, use the following resources to troubleshoot a content switching issue on a Citrix ADC appliance:

  • Configuration file
  • Relevant newnslog file
  • Trace files
  • Network topology diagram for the network setup of the customer
  • Citrix documentation, such as release notes, Knowledge Center articles, and eDocs

In addition to the above resources, the following tools expedite troubleshooting:

  • The iehttpheaders or a similar utility
  • The Wireshark application customized for the Citrix ADC trace files
  • An SSH utility for command line access
  • A HyperTerminal utility to access the console

Troubleshooting Content Switching Issues

The most common content switching issues involve the content switching feature not working at all, or working only intermittently, and Service Unavailable responses.

  • Issue

    The content switching feature is not functioning.

    Resolution

    Check the configuration as follows:

    • Verify that the appliance is licensed for content switching.
    • Verify that the feature is enabled.
    • From the configuration file, verify that valid content switching policies are correctly bound to the load balancing virtual servers.
  • Issue

    Client receives a 503 - Service Unavailable response.

    Resolution

    • Verify the URL and policy bindings. The client receives the 503 response when none of the policies you have configured is evaluated and no default load balancing virtual server is defined and bound to the content switching virtual server.
    • From the configuration, verify the policies and URL being accessed by the client.
    • Verify that for every type of request the respective policy is evaluated. If the policy is not evaluated, check the policy expression and update it if necessary.
    • Verify the URL and HTTP request and response headers. To do so, record an HTTPHeader trace and, if necessary, record the packet traces on the appliance and the client.
  • Issue

    Intermittently, the content switching feature is not working as expected.

    Resolution

    • Study the network topology diagram, if available, of the setup to understand the various devices installed between the client and the server(s).

    • Verify the configuration and policy bindings. Make sure that the URL in the policy expression matches to the one in the client request.

    • Verify that appropriate priorities are assigned to the policies. An incorrect precedence or priority assigned to a policy can cause a problem.

    • Run the following commands to verify the bindings and the values of the policy hit counters in the output of the commands:

      show cs vserver <CS VServer>

      show cs policy <CS Policy>

      stat cs vserver <CS VServer>

    • Using iehttpheaders or a similar utility, determine whether the HTTP headers for the requests or responses provide any pointers to the issue.

    • Check the release notes and Knowledge Center articles.

    • If the issue is still not resolved, contact Citrix Technical Support with appropriate data for further investigation.

Troubleshooting