Windows XP is available in two editions - Home Edition for home use, and Professional for businesses. Security features in the Home edition make it even safer for you to shop and browse on the Internet. It comes with a built-in Internet Connection Firewall software that provides you with a resilient defense mechanism against security threats when you're connected to the Internet, particularly if you use always-on connections such as cable modems and DSL. Security in Home Edition This version's security services have been designed to be flexible, and take into account a wide variety of security and privacy situations that you'll face as a home user. Personalized Login: With Windows XP, all family members can have their own interface, complete with login and password. This added level of security ensures that no one can access, or accidentally delete your important documents. If you have children in the house, you can set up profiles with different security limits to filter out Internet sites that may be inappropriate for them. Fast User Switching for Multiple Users of a Computer: Designed for the home, Fast User Switching lets everyone use a single computer as if it were their own. There is no need to log someone else off and decide whether to save another user's files. Instead, Windows XP takes advantage of Terminal Services Technology and runs unique user sessions that enable each user's data to be entirely separated. And when used with a user password, these sessions are secured from one another. Personal Privacy: Microsoft Internet Explorer version 6.0 helps you maintain control over your personal information, when visiting web sites, by supporting the Platform for Privacy Preferences (P3P) standard from the World Wide Web Consortium (W3C). As part of W3C, Microsoft helped develop a standard for web site privacy policies, so that you can make informed decisions about the amount and type of information you share online. Internet Explorer 6.0 determines whether the web sites you visit adhere to the standards Of W3C and tells you their status before you provide private information. Once you have defined your privacy preferences for disclosing personal information in Internet Explorer 6.0, the browser determines whether the sites you visit are P3P-compliant. For P3P-compliant sites, the browser compares your privacy preferences to the privacy policies defined for the sites. Internet Explorer uses HTTP for this exchange of policy information. Based on your privacy preferences, the browser determines whether to disclose personal information to the web sites. Cookie Management: The P3P standard also supports cookie management features in Internet Explorer 6.0. A cookie is a small file that an individual web site stores on your computer, to provide customization features. For example, when you implement custom settings for MSN®, that information is stored in a cookie file on your computer. MSN then reads the cookie each time you visit the site and displays the options you selected. As part of their privacy policies, P3P-compliant web sites can provide policy information for their cookies. When you configure your privacy preferences, you can configure Internet Explorer to handle cookies in the following ways: - Prevent all cookies from being stored on your computer. - Refuse third-party cookies (cookies that do not originate from the same domain as the web site being visited and therefore are not covered by that web site's privacy policy), but allow all other cookies to be stored on your computer. Internet Connection Sharing: Internet Connection Sharing (ICS) connects multiple computers to the Internet using a single connection. With ICS, users can securely share DSL, cable modem, or telephone line connections among multiple computers. How ICS Works One computer, called the ICS host, connects directly to the Internet and shares its connection with the rest of the computers on the network. The client computers rely on the ICS host computer to provide access to the Internet. Security is enhanced when ICS is enabled because only the host computer is visible to the Internet. Any communication from client computers to the Internet must pass through the host, a process that keeps the addresses of client computers hidden from the Internet. Client computers are protected, because they cannot be seen from outside the network. Only the computer running ICS is seen from the public side. In addition, the ICS host computer manages network addressing. The host computer assigns itself a permanent address and provides Dynamic Host Configuration Protocol (DHCP) to ICS clients. By assigning a unique address to each ICS client, it provides a way for computers to communicate with other computers on the network. Windows XP provides the ability to share a single Internet connection with multiple computers on a home or small-business network through the ICS feature. This feature first appeared in Windows 2000 Professional and Windows 98 Second Edition, and has been improved in Windows XP. Using Network Protocols: In Windows XP, the ICS feature provides Network Address Translation (NAT), DHCP, and Domain Name Service (DNS) to the home network. Configuration of clients: The DNS functionality in Windows XP has been improved to include a local DNS Resolver to provide name resolution for all clients on the home network. With the DNS Resolver, non-Windows-based network devices are able to conduct name resolution for network clients. Internet names needing resolutions are still forwarded to the Internet service provider's DNS servers for resolution. Remote Discovery and Control Functionality: ICS also includes remote discovery and control functionality. Using Universal Plug and Play, network clients detect the presence of the ICS host, then query and determine its Internet connection status. When you want to browse the Internet on another personal computer within your home, the Windows XP personal computer automatically connects to the Internet, if it's not already connected on behalf of the other computer. The user on the client computer elsewhere in the house will know if there's an existing Internet connection, and can disconnect it to use the telephone for normal voice communications, if desired. This is useful if you're charged by the minute for dial-up connections, or prefer to turn off your Internet connection during periods of inactivity. Internet Connection Firewall: Windows® XP provides Internet security in the form of the new Internet Connection Firewall (ICF). For years, business networks have been able to protect themselves from outside attacks by using firewalls. The Windows XP ICF makes use of active packet filtering, which means that ports on the firewall are dynamically opened only for as long as needed to enable you to access the services you're interested in. This type of firewall technology, which is usually associated with more sophisticated enterprise firewalls, prevents would-be hackers from scanning your computer's ports and resources, including file and printer shares. This significantly reduces the threat of external attacks. This firewall feature is available for Local Area Network (LAN), Point-to-Point Protocol Over Ethernet (PPPoE), VPN, or dial-up connections. Windows XP is the first Microsoft operating system to include this native PPPoE support. Shared Documents Folder: When you create a password for yourself, Windows offers to lock down your "My Documents" folder, as well as any other sub-folder. That way, if you have a password and want privacy, you will be protected from other non-administrator users of the computer.