Security levels and zones are core parts of Internet Explorer’s security features. You can display security options for Internet Explorer by clicking Tools, selecting Internet Options, and then clicking the Security tab in the Internet Options dialog box.

By default, Internet Explorer always runs in protected mode. You can enable or disable protected mode by selecting or clearing the Enable Protected Mode check box. The standard levels of security that you can use are:

• High This level is appropriate for sites that might contain harmful content. Internet Explorer runs in its highest protected mode with maximum safeguards and in which less secure features are disabled.

• Medium-high This level is appropriate for most sites. Internet Explorer prompts you prior to downloading potentially unsafe contents and disabling downloading of unsigned ActiveX controls.

  Note:

  Medium-high is a new security level in Internet Explorer 7, and it is also the default level for the Internet security zone.

• Medium This level is appropriate only for trusted sites. In this mode, Internet Explorer prompts you prior to downloading potentially unsafe contents and disables downloading of unsigned ActiveX controls.

• Medium-low This level is appropriate only for sites on your internal network. In this mode, Internet Explorer runs most types of content without prompting but does disable downloading of unsigned ActiveX controls.

• Low This level is appropriate only for sites you absolutely trust, such as secure internal sites. In this mode, Internet Explorer uses minimal safeguards, and most content is downloaded and run without prompts.

To help you manage when the various security levels should be used, Internet Explorer defines four standard security zones:

• Internet This zone is for Internet sites, except those listed in trusted and restricted zones. By default, the Internet zone uses medium-high security.

• Local Intranet This zone is for all sites that are on your internal network (intranet). By default, the Local Intranet zone uses medium-low security.

• Trusted Sites This zone is for all sites that you have specifically identified as trusted and requiring the lowest level of safeguarding against possible damage. By default, the Trusted Sites zone uses a custom security level that is close to medium security.

• Restricted Sites This zone is for all sites that you have identified as restricted and requiring the highest level of safeguarding against possible damage. By default, the Restricted Sites zone uses high security.

You can change the default behavior by setting a new security level for a zone, if permitted. For example, you could increase security for the Internet zone by setting the security level to High. With any security levels except Restricted Sites, you can set a custom security level as well. With a custom security level, you configure individual security settings for content and downloads in any way desired.

In addition to creating the new medium-high security level, Internet Explorer prevents you from using certain security levels in some security zones. When working with security zones and levels, you’ll need to keep the following in mind:

• In the Internet security zone, only the high, medium-high, and medium security levels are available. However, you can set a custom security level that is less secure. If you select the Internet zone and click the Default Level button, the security level is set to Medium-High.

• In the Local Intranet security zone, any of the security levels can be used. If you select the Local Intranet zone and click the Default Level button, the security level is set to Medium-Low.

• In earlier versions of Internet Explorer, trusted sites use a custom low security level. Now trusted sites use a custom medium security level by default. If you select the Trusted Sites zone and click the Default Level button, the security level is set to Medium.

• In earlier versions of Internet Explorer, restricted sites use a custom high security level that you can reset to any other security level. Now restricted sites use a nonconfigurable high security level. However, you can set a custom security level that is less secure.

  For the Internet and Restricted Sites zones, Internet Explorer displays a warning on the information bar specifying that your security settings put your computer at risk if you use a custom security level lower than the default security level. You can restore the default security level by right-clicking the information bar and then selecting Fix Settings For Me. When prompted, click Fix Settings to restore the defaults.