To enable anonymous access for a web application within SharePoint:
1. Go to Central Administration >> Application Management >> Authentication Providers.
- make sure to pick correct web application from the drop-down list at the top-right corner of the page.
- select the Membership Provider (most likely it will be "Default") and enable check "Enable anonymous access" checkbox.
- click OK to save the settings.
2. The step above will usually enable anonymous access in IIS Manager, but just be sure:
- open IIS Manager
- right-click on your website and click on "Edit" under Authentication and Access Control
- make sure "Enable anonymous access" is checked
3. We now need to explicitly enable anonymous access on our website(s)
- browse to the website
- click Site Actions >> Site Settings >> People and Groups >> Site Permissions
- click on Settings >Anonymous Access and enable anonymous access for the site
* Anonymous access will be also enabled on all subsites that inherit security settings from the parent site.
Related resources: