Outlook Security Zones

Issue

E-mail can possibly contain harmful HTML content that, when downloaded and executed, can harm files, programs, or system security.

Solution

In Microsoft Outlook XP, Outlook 2000, and Outlook 98, you can use security zones to limit access from incoming e-mail messages with HTML content. These security zones provide advanced protection against certain types of files that might gain access to your computer, and replace or damage files. Users can choose which security zone to use for incoming e-mail messages, and they can select one of the following five levels of security for each zone:

• High is the most secure. It excludes content that might damage your computer.
• Medium excludes some content and provides a warning before opening content that is potentially damaging.
• Medium-Low excludes some content, but does not provide a warning.
• Low is the least secure. It does not exclude or provide a warning before running potentially damaging content.
• Custom is for expert users. It allows you to choose from a list of content types and specify enabled, disabled, or prompt for each content type.

Outlook provides four security zones:

• Local intranet contains all Web sites that are on your organization's intranet. The default security level for this zone is Medium-Low.
• Trusted sites contains Web sites that you trust will not damage your computer. By default, there are no Web sites assigned to this zone, and the security level is set to Low.
• Restricted sites contains Web sites that could potentially damage your computer or data. By default, there are no Web sites assigned to this zone, and the security level is set to High.
• Internet contains all Web sites you have not placed in other zones. The default security level for this zone is Medium.

For maximum security, Outlook should operate within the Restricted sites zone.

Note: Zones that have Custom settings may be more secure than the recommended settings in the tool. While the tool will report that custom settings are used for each zone, it cannot determine whether these settings are more secure than the recommended setting.

To change the security zone settings in Outlook

1. On the Tools menu, click Options.
2. Click the Security tab, click Zone Settings, and then click OK when prompted.
3. In the Security dialog box, click the zone for which you want to set the security level.
4. Under Set the security level for this zone, click the security level that you want to set for the selected zone.  If you click Custom Level, you must click Settings, and then, in the Security Settings dialog box, you need specify the individual settings that you want to apply.

Additional Resources

OL2000: Security Zones in Outlook 2000 (Q196799)

OL98: Security Zones in Outlook 98 (Q182729)

OL2000: Why Outlook Requires Internet Explorer 4.01 or Later (Q230063)

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