How do keywords and regular expressions work?

Keywords and regular expressions are ways to identify types or groups of related URLs for special handling.

• A keyword is a string of characters (a word, phrase, number, or acronym) that might be found in a URL.

  When you create a keyword, you associate it with a category. When your software finds that keyword in a URL, it assigns the URL to the category that you have selected, and blocks the URL.

  Keywords are used only to recategorize and block URLs; they cannot be used to permit URLs.

• A regular expression is a template or pattern used to match multiple strings, or groups of characters. Regular expressions can be used:
  • To identify groups of related URLs in limited access filters and exceptions
  • As a more flexible form of keyword, to assign URLs to categories for blocking

  When you use regular expressions, Filtering Service tries to match the general pattern, rather than a specific, single URL or keyword. Regular expressions match precise terms and are case sensitive.

Use keywords and regular expression with caution to avoid unintended over blocking or under blocking.