Configuring Browsers for Cookies and ActiveX

ActiveX controls are small programs that are downloaded by a browser and executed on the user's computer. For example, it is possible for a malicious ActiveX control to reformat a user's hard disk drive or wipe out critical system files.
You can configure Internet Explorer to set automatic ActiveX control activation as your default. Otherwise, potentially malicious ActiveX controls or plug-ins may run without signature checking or without your knowledge.

Web sessions can be tracked using cookies. Cookies are small (up to 4K) pieces of information (i.e., text files) stored on the client machine and associated with a particular server. Cookies create a complete list of all Web sites the user visits and all activities the user performs. When used properly, cookies can be an Internet user's best friend because they facilitate the display of information most valued to that user.
When misused, they have to potential to invade one's privacy. Since the server can potentially act on the information it collects, the cookie feature has security and privacy implications for the unwary user. However, you can tell the browser not to accept cookies.

One of the most attractive features of ActiveX technology is the ways in which components can be created. Figure 2-9 illustrates the ActiveX family, including tools that can be used to develop controls. An ActiveX control is defined as "a software component that performs common tasks in standard ways." The ActiveX controls specification specifies a standard set of interfaces that COM objects can support to carry out particular actions. Components need to interact with the code that uses them, and the ActiveX controls specification determines rules for creating so-called control containers.

A control container is client software that knows how to use an ActiveX control. Applications developed using different computer languages, such as Visual Basic and C++, Java, can serve as control containers. Web browsers, such as Microsoft Internet Explorer, also are examples of containers. Netscape Navigator did not originally support ActiveX. As a result, web pages containing ActiveX controls did not function properly in Netscape browsers. ActiveX controls for the Web are simple objects on a Web page that provide a user interface and support these interfaces. They add an interactive component to the page and allow users to communicate with the page. The code for a control can also be stored on aWeb server and downloaded and executed when the browser or Web page requests them. An ActiveX control is compiled code with file extension.ocx.

As shown in the Internet Explorer Properties dialog box below, you can:

1. Accept all cookies
2. Accept cookies on a case-by-case basis
3. Never accept cookies

Since cookie files take up space on your desktop machine, you may want to delete the cookie file or some of its entries. On the Macintosh, the cookie file is called MagicCookie. On Windows-based machines, there is a cookie folder containing individual cookie files.
In the next lesson, how protocols are used in sending and receiving email will be discussed.