Product Documentation

Configuring a Responder Action

After enabling the responder feature, you must configure one or more actions for handling requests. The responder supports the following types of actions:

  • Respond with. Sends the response defined by the Target expression without forwarding the request to a web server. (The Citrix ADC appliance substitutes for and acts as a web server.) Use this type of action to manually define a simple HTML-based response. Normally the text for a Respond with action consists of a web server error code and brief HTML page.
  • Respond with SQL OK. Sends the designated SQL OK response defined by the Target expression. Use this type of action to send an SQL OK response to an SQL query.
  • Respond with SQL Error. Sends the designated SQL Error response defined by the Target expression. Use this type of action to send an SQL Error response to an SQL query.
  • Respond with HTML page. Sends the designated HTML page as the response. You can choose from a drop-down list of HTML pages that were previously uploaded, or upload a new HTML page. Use this type of action to send an imported HTML page as the response.
  • Redirect. Redirects the request to a different web page or web server. A Redirect action can redirect requests originally sent to a “dummy” web site that exists in DNS, but for which there is no actual web server, to an actual web site. It can also redirect search requests to an appropriate URL. Normally, the redirection target for a Redirect action consists of a complete URL.

To configure a responder action by using the Citrix ADC command line:

Displays the current settings for the specified responder action. If no action name is provided, displays a list of all responder actions currently configured on the Citrix ADC appliance, with abbreviated settings.

At the command prompt, type the following commands to configure a responder action and verify the configuration:

  • add responder action <name> <type> <target> [-bypassSafetyCheck (YES | NO) ]
  • show responder action

Parameters:

  • Name. Name of the responder action. Maximum Length: 127

  • type. Type of responder action. It can be: (respondwith).

  • target. An expression specifying what to respond with

  • htmlpage. Option specifying to respondwith htmlpage

  • bypassSafetyCheck. The safety check to allow unsafe expressions. Note: This attribute is deprecated.

  • hits. The number of times the action has been taken.

  • referenceCount. The number of references to the action.

  • undefHits. The number of times the action resulted in UNDEF.

  • comment. Any type of information about this responder action.

  • builtin. Flag to determine whether responder action is built-in or not

Example:

To create a responder action that displays a “Not Found” error page for URLs that do not exist:

> add responder action act404Error respondWith '"HTTP/1.1 404 Not Found\r\n\r\n"+ "HTTP.REQ.URL.HTTP_URL_SAFE" + "does not exist on the web server."'
Done

> show responder action

1\) Name: act404Error
Operation: respondwith
Target: "HTTP/1.1 404 Not Found

"+ "HTTP.REQ.URL.HTTP_URL_SAFE" + "does not exist on the web server."
BypassSafetyCheck : NO
Hits: 0
Undef Hits: 0
Action Reference Count: 0
Done

To create a responder action that displays a “Not Found” error page for URLs that do not exist:

add responder action act404Error respondWith '"HTTP/1.1 404 Not Found\r\n\r\n"+ "HTTP.REQ.URL.HTTP_URL_SAFE" + "does not exist on the web server."'
Done
> show responder action

1\) Name: act404Error
Operation: respondwith
Target: "HTTP/1.1 404 Not Found

"+ "HTTP.REQ.URL.HTTP_URL_SAFE" + "does not exist on the web server."
BypassSafetyCheck : NO
Hits: 0
Undef Hits: 0
Action Reference Count: 0
Done

To modify an existing responder action by using the Citrix ADC command line:

At the command prompt, type the following command to modify an existing responder action and verify the configuration:

  • set responder action -target [-bypassSafetyCheck ( YES | NO )]
  • show responder action

Example:

set responder action act404Error  -target '"HTTP/1.1 404 Not Found\r\n\r\n"+ "HTTP.REQ.URL.HTTP_URL_SAFE" + "does not exist on the web server."'
 Done
> show responder action

1)      Name: act404Error
        Operation: respondwith
        Target: "HTTP/1.1 404 Not Found

"+ "HTTP.REQ.URL.HTTP_URL_SAFE" + "does not exist on the web server."
        BypassSafetyCheck : NO
        Hits: 0
        Undef Hits: 0
        Action Reference Count: 0
 Done

To remove a responder action by using the Citrix ADC command line:

At the command prompt, type the following command to remove a responder action and verify the configuration:

  • rm responder action
  • show responder action

Example:

rm responder action act404Error
 Done

> show responder action
 Done

To configure a responder action by using the GUI:

  1. Navigate to AppExpert > Responder > Actions.
  2. In the details pane, do one of the following:
    • To create a new action, click Add.
    • To modify an existing action, select the action, and then click Open.
  3. Click Create or OK, depending on whether you are creating a new action or modifying an existing action.
  4. Click Close. A message appears in the status bar, stating that the feature has been enabled.
  5. To delete a responder action, select the action, and then click Remove. A message appears in the status bar, stating that the feature has been disabled.

To add an expression by using the Add Expression dialog box

  1. In the Create Responder Action or Configure Responder Action dialog box, click Add.

  2. In the Add Expression dialog box, in the first list box choose the first term for your expression.
    • HTTP. The HTTP protocol. Choose this if you want to examine some aspect of the request that pertains to the HTTP protocol.

    • SYS. The protected web site(s). Choose this if you want to examine some aspect of the request that pertains to the recipient of the request.

    • CLIENT. The computer that sent the request. Choose this if you want to examine some aspect of the sender of the request.

    • ANALYTICS. The analytics data associated with the request. Choose this if you want to examine request metadata.

    • SIP. A SIP request. Choose this if you want to examine some aspect of a SIP request.

    When you make your choice, the rightmost list box lists appropriate terms for the next part of your expression.

  3. In the second list box, choose the second term for your expression. The choices depend upon which choice you made in the previous step, and are appropriate to the context. After you make your second choice, the Help window below the Construct Expression window (which was blank) displays help describing the purpose and use of the term you just chose.
  4. Continue choosing terms from the list boxes that appear to the right of the previous list box, or typing strings or numbers in the text boxes that appear to prompt you to enter a value, until your expression is finished.

Configuring the Global HTTP Action

You can configure the global HTTP action to invoke a responder action when an HTTP request times out. To configure this feature, you must first create the responder action that you want to invoke. Then, you configure the global HTTP timeout action to respond to a timeout with that responder action.

To configure the global HTTP action by using the Citrix ADC command line:

At the command prompt, type the following command:

  • set ns httpProfile -reqTimeoutAction <responder action name>

  • save ns config

For <responder action name>, substitute the name of the responder action.

Configuring a Responder Action