URL Filtering in IWSVA is a feature to filter Internet access that is based on the categories of URLs, such as “Adult”, “Gambling,” and “Financial Services.” When a user requests a URL, IWSVA first looks up the category for that URL and then allows or denies access to the URL, displays warning, overrides password, or sets time quota based on the policies administrator has set up.
For a specific URL category, there are six actions in IWSVA: “allow” to permit the access; “block” to stop the access; "block with override" to enter password to override the blocking, “monitor” to allow the access but log the action silently; "time limit" to set a time quota for selected URL categories, and "warn" alerts the user that there is a problem with the URL they are accessing. Block with Override mode might be used instead of just blocking or monitoring because:
Some websites contain harmful code or the contents violate company policy. IT admins must block access to these websites. But sometimes, useful information can be found at these websites. Block with password override provides a mechanism that allows someone to visit the blocked websites under the control of IT admin. This could improve company efficiency.
The "block with override" feature is used to temporarily allow an authorized person to override the blocking rule for URL filtering. This feature is desired in many schools, libraries, and commonly shared computer labs. For these types of environments, having the ability to override a URL block by an approved user such as a teacher, librarian, or supervisor is critical.