HOWTO: Allow access as an anonymous user with FBA and SharePoint 2010

Question

I have a new site with a custom forms membership and role provider, and I need to allow anonymous users to visit the site (i.e. to browse around but not log in). This is a new SharePoint 2010 site running under claims authentication (obviously).

Problem I have is that despite allowing anonymous access in both central admin and site permissions, the user is auto redirected to the login page whenever they visit or try to move around the site. In fact, there seems to be a loop, as envisaged by the url below (for ease, I set the homepage to be the login page, as the login control is a web part on the homepage).

/pages/default.aspx?ReturnUrl=%2f_layouts%2fAuthenticate.aspx%3fSource%3d%252FPages%252FDefault%252Easpx&Source=%2FPages%2FDefault%2Easpx

How do I configure a 2010 site to allow usage for anonymous users without forcing them to log in?

Answer 1

Fixed it. Even though Anonymous Access was set to the entire web site, the site was still throwing an access denied for a request for a resource from the local style library. Discovered this by trawling the sharepoint event logs, specifically for 'Access Denied' and 'Authenticate.aspx'. Code I had written would try to find a resource in the style library before checking the file system, so its possible the access denied was thrown because the file was not there, or because this library has its own permission structure. FML.