Before you can configure a site to allow anonymous access, the associated web application must first have anonymous access enabled through Central Administration. If the web application is set through Central Administration to allow anonymous access, you can control what parts of your site are visible to anonymous users. If the central administrator has not enabled anonymous access for the web application, the functionality will not be visible. Follow these steps to enable anonymous access for the web application:
1. Open the Central Administration site by selecting Start ä Administrative Tools SharePoint 3.0 Central Administration.
2. In the Central Administration site, click the Application Management tab.
3. Under the Application Security section, click the link titled Authentication Providers.
4. On the Authentication Providers page, make sure that the correct web application is
selected. If not, drop the menu and select Change Web Application.
5. On the Authentication Providers page, click the Default Zone link.
6. On the Edit Authentication page, check the box labeled Enable Anonymous Access.
7. Click the Save button.
Once the web application is configured for anonymous access, you can return to the Permissions page. From the Permissions page, you can select Settings Anonymous Access to open the Anonymous Access Settings page. On this page, you may select to expose the entire site, all lists and libraries, or nothing at all. Additionally, you can control the visibility of an individual list or library through its permission settings. This combination of site-level and list-level configuration gives you a good deal of control over what parts of the site can be accessed anonymously.