Security Zones

Web applications are capable of doing almost anything a standard Windows application can do, including interacting with the desktop, installing software, and changing your computer's settings. However, if Web browsers allowed Web sites to take these types of actions, some Web sites would abuse the capabilities to install malware or perform other malicious acts on computers.

To reduce this risk, Internet Explorer limits the actions that Web sites on the Internet can take. However, these limitations can cause problems for Web sites that legitimately need elevated privileges. For example, your users might need to visit an internal Web site that uses an unsigned ActiveX control. Enabling unsigned ActiveX controls for all Web sites is very dangerous, however.