I’m currently involved in a project where we publish multiple SharePoint sites using UAG 2010. These SharePoint sites require users to be authenticated using claims. These claims are provided from an AD FS 2.0 farm. When we first applied SP2 for UAG in our lab we noticed that our Single Sign On experience was broken. When we visited a SharePoint URL, we expected to be greeted with the UAG logon form followed by the SharePoint site itself.

Here’s the UAG logon form:

However, after choosing login we saw the following login form. It was fixed to our “ADFS” server we defined in UAG. No matter what credentials we entered, we didn’t got past this form.

After reverting the virtual machine its snapshot, yes I took one! ; ) I could see that SSO was working again as expected. So I switched back the snapshot to where SP2 was installed and started troubleshooting. I tried several things, but nothing worked. So in the end we logged a case with Microsoft. One of the things I had tried, and which the engineer asked me to do as well was the following:

This was how I set it up the authentication of one of the SharePoint sites initially:

This is how he asked me to set it up:

After changing this setting, we got rid of the second form, but now we got an additional “basic authentication” login popup…. After sending over some debug logs and so the engineer suggested to revert back the snapshot to before installing SP2 and to try reinstalling SP2. And I still have no idea why, but everything worked after reinstalling SP2.

Bottom line: when publishing a site which uses claims for authentication, you shouldn’t specify AD FS as an SSO server for the published site. The web application will redirect the user to the ADFS service, and UAG handles SSO towards the ADFS service. But with UAG 2010 pre SP2 either approach worked fine so I didn’t questioned this.

Here you can see an other (unrelated) change in the ADFS configuration when using claims based authentication for the UAG trunks. Before you had to explicitly check “allow unauthenticated access to the web server”. After SP2 the check box is gone.