Validate or Change Content Type Assertion (Threat Protection)

The Validate or Change Content Type assertion can be used to validate the Content-Type of any target message and to change the Content-Type of request messages. You can target specific parts of a multi-part MIME message.
To learn about selecting the target message for this assertion, see Select a Target Message.
To change the Content-Type header for a response message, use the Manage Transport Properties/Headers Assertion instead.
Using the Assertion
  1. Do one of the following:
    • To add the assertion to the Policy Development window, see Add an Assertion.
    • To change the configuration of an existing assertion, proceed to step 2 below.
  2. Right-click <target>: Validate Content Type or <target>: Change Content Type to < ContentType> in the policy window and select Content Type Properties or double-click the assertion in the policy window. The assertion properties are displayed.
  3. Configure the properties as follows:
    Message part index
    Select this check box to target the Content-Type in a specific MIME part in the message.
    Clear this check box to target the Content-Type in the main/root MIME part of the message (for example, MIME part '1').
    Validate syntax of content type
    Select this option to validate the syntax of the value of the Content-Type of the targeted message or message part.
    • If the validation succeeds, the assertion succeeds.
    • If the validation fails, the assertion fails and returns the assertion status code 601 ("Error in assertion processing.")
    Change content type
    Select this option to modify the Content-Type value of the targeted message or message part.
    The modification takes effect immediately, but any previous message processing performed using the old Content-Type is not reversed .
    New valu
    When changing the Content-Type, enter the new value here. You can also enter a context variable to set the value at the time of policy execution.
    The value must be a valid and complete MIME type as defined by RFC 2045 and 2046.
    Reinitialize message
    When changing the Content-Type, you can optionally reinitialize the message. This rebuilds the parts of the message and can be used to fix an incorrect Content-Type.
    Consider reinitializing if you are changing the Content-Type from single part to multipart or vice versa. There is no harm in reinitializing when not required, however there is a slight performance impact.
  4. Click [OK] when done.