To enable anonymous access on SharePoint 2010, it is important to first understand the hierarchy of some SharePoint terms: Web Application, Site Collection, Site, Library and List. Under each Web Application, you can create Site Collections; in each Site Collection, you can create Sites and Sub-sites; in each SharePoint site, you can create libraries or lists under which you can create/upload content items. To enable Anonymous Access of a SharePoint site, library or list, you need to start from the top level.
Web Application Level
Step1: Open SharePoint 2010 Central Administration (Path: Start MenuàAll ProgramsàMicrosoft SharePoint 2010 ProductsàSharePoint 2010 Central Administration)
Step 2: Click Manage web applications under Application Management:
Step3: Select the Web Application you want to add Anonymous Access, and then click Authentication Providers
Step 4: Choose the Default zone to edit:
Step 5: Check Enable anonymous access option, click Save and then close the Edit Authentication window:
Step 6: From the ribbon on the Manage Web Application Page, click Anonymous Policy
Step 7: Select a Zone to apply the policy, choose User Policy and then click Save
After Anonymous Access is set up in the Web Application where the site collection resides, you can now set the anonymous access permissions settings at the site level:
Step 1: Go to the site where you need to allow Anonymous Access, click Site Actions, click Site Permissions:
Step 2: In the ribbon, click Anonymous Access:
Note: If you are working with a sub-site that is inheriting permissions from the parent site, you need to first break the inheritance by clicking Stop Inheriting Permissions:
You will see the following message, click OK
Step 3: In the Anonymous Access settings page, specify which parts of the Web sites anonymous users can access. If you choose Lists and Libraries option, only the lists and libraries that have enabled anonymous user access will allow anonymous access:
Click OK and you can see that Anonymous Users access has been added:
Libraries and Lists level
Step 1: Go to the list or library where you want to enable anonymous access.
List ToolsàListàSettingsàList Permissions
Step2: Click Anonymous Access in the Ribbon:
Note: If you are working with a list that is inheriting permissions from its parent site, you need to first break the inheritance by clicking Stop Inheriting Permissions:
Step3: Select permissions anonymous users have in the list/library and then click OK:
Congratulations! You’ve just configured Anonymous Access settings at Web Application level, Site level and Library/List level. Note that you should take security into consideration when enabling anonymous access. It makes a Web server inherently less secure because anonymous users’ actions cannot be traced to an authenticated user account.