Multiple logins for opening office documents saved in document library in SharePoint 2010 using Claims Based Authentication

Question

Our environment is Sharepoint 2010, with a web application created (and site collection on top), using claims based authentication. The first site is using port 881. It is using integrated windows authentication. Another web application is created, extending the first application, using port 882. This site is using Forms Based Authentication, the membership provider is System.Web.Security.ActiveDirectoryMembershipProvider, named admembers. I have turned off Client Integration on both sites.

When I login to the 881 site, on my corporate network, logged into the machine with the same domain account that sharepoint uses, I can open an Office file saved in a document library, and it subsequently opens in the appropriate Office application, without asking me login again. But, If I login to Sharepoint from a computer that is not on our network, or login to the computer with an account that is not a domain account, I get prompted again to login when openning an Office document. If I choose the option to save, it does not prompt, but if I choose open in the dialog window, I am forced to enter my domain credentials again.

When I login to the 882 site, which uses FBA, I experience the same problem. If I open an Office document, the appropriate Office application opens, and asks me for my credentials, by showing me a dialog window with the sign in page loaded. If I choose to save the file, then I am not prompted to login, and the file saves to a local folder.

I can't expect my users that are off site to login again everytime they open an Office document, like Work, Excel, Powerpoint, etc. I have tried numerous fixes, including disabling client integration, changing the browser handling mode (strict/permissive), changing internet explorer settings (for integrated windows authentication), changing the integrated windows authentication site to use basic authentication, even hacking the page using jquery to call the sharepoint javascript function that execute the "download a copy" function. None of them work: when choosing to "open" the Office document in the browser, the user has to login again, or just close the dialog window without logging in (as long as client integration for the zone is turned off).

I'm looking to get this accomplished using windows authentication or forms based authentication.

Help!

Answer 1

I found this answer in a similar post which seemed to fix the problem for me when I tested it. The gist of it is you need to deny the HTTP Verbs OPTIONS and PROPFIND in IIS. Having said this, I'm not an IIS guru and am not exactly sure what this means or what else it might affect. Can anyone else shed some light on this?

A bit of background, I'm using SharePoint 2010, on an FBA site.

Answer 2

You have the standard three use cases:

1. Employee intranet access
2. Employee remote access
3. Partner remote access

Employee intranet access

This normally always works out of the box, and it looks like it is working for you.

Employee remote access

The only way that i have seen this work (and i have tried many ways) is to get TMG or ISA. Basically ISA is setup in FORMS auth with SSL, it captures the auth details, and then passes them to the sharepoint server. (and other servers if you have them eg OWA for sharepoint mail web parts) If you select the "Is private computer" option on the ISA login screen, then Office documents share the auth cookie and don't prompt for another login. I had so many problems, but as soon as i installed TMG, they all went away. I would not recommend any other approach now.

The added bonus of this method, is that remote employees are treated as the same account as the intranet user. The way you are setup with a seperate web application, means that they will be different accounts, so things like [checkout/modifiedby/createdby/personalisation] will be different accounts (though they look the same)

Partner remote access

This may never ever work on some clients (especially Vista), as IE needs to share the authentication with Office