NetGuard - Version 1.01 A Java-based Network Security Scanner, the first of its kind. It scans TCP/IP networks looking for security holes that are commonly exploited by intruders. NetGuard runs on any Java 1.1 platform. If you do not have Java installed, the installation program will lead you to download it as well. Pricing starts at $199, and is highly recommended for any network, especially one connected to the Internet.