Exam 1Y0-341 topic 1 question 96 discussion

Default profile—The profile applied to connections that do not match a policy. https://docs.netscaler.com/en-us/citrix-adc/current-release/application-firewall/configuring-global-settings/engine-settings.html

"Undefined profile" is specifically used when an advanced policy expression cannot be evaluated to a definite true or false.

The "Default profile" setting in the Citrix Web App Firewall engine settings is applied to connections that do not match any policy. It is a catch-all profile for traffic that has not been otherwise specified by Web App Firewall policies. On the other hand, the "Undefined profile" is specifically used when an advanced policy expression cannot be evaluated to a definite true or false. This situation may arise if an expression is malformed or if certain variables in the expression are missing or cannot be processed. In such cases, the undefined profile ensures that there is a predefined action or set of actions that the Web App Firewall will enforce, thus providing a safeguard against requests that fall into this indeterminate state.