SharePoint 2010: Fix – The RSS WebPart does not support authenticated feeds.

I recently ran into an issue when adding an RSS Feed WebPart into one of my SharePoint 2010 Sites when linking an internal SP list as the RSS feed.  When doing so I received the following error:

“The RSS WebPart does not support authenticated feeds”

Within SharePoint 2010 to get RSS WebParts to work successfully with internal RSS feeds you have to make sure your site is Kerberos enabled.  If not your RSS WebParts will not work.  External RSS feeds will work fine on none Kerberos enabled web applications.

In my case I had Kerberos enabled, SSL set, SPNs set, and had anonymous access disabled, since in my environment we leverage a PKI Token base authentication through TMG. Ideally this should work fine, but there was one last step that I needed to do to bypass the above error.

Within the web.config file of the (Kerberos) Web Application that will  host the RSS Feed WebPart I also had to update the AllowAnonymousImpersonation setting to FALSE on all the WFE’s.

1.  Open up web.config file for (Kerberos) Web Application
2.  Search for AllowAnonymousImpersonation
3.  Change the following element:

<add key=”aspnet:AllowAnonymousImpersonation” value=”true” />

to

<add key=”aspent:AllowAnonymousImpersonation” value=”false” />

4.  Save web.config file

Now when I browse the site with the RSS Feed WebPart the webpart should render the list feed with no problem.