From the SBS partner forums.. I spotted a post about the issue where SharePoint is now flipped to Kerberos and how one can manually check to ensure that Kerberos setting is as it should be…..
The typical symptom of the issue addressed by update rollup 2 is that you will be prompted for authentication 3 times and eventually receive a blank page or 401.1 error. IIS logs will show your request failing with 401.1 Unauthorized.
(The IIS log for Companyweb is located in C:\inetput\logs\LogFiles\W3SVC442802965 folder. )
To determine if update rollup 2 is installed, please check:
1. Check Control Panel -> Program and Features -> View Installed Updates to see if ‘Update Rollup 2 for Windows Small Business Server 2008 (KB960911)’ is listed.
2. After installing rollup 2, the authentication mode of the http://companyweb Web site should be changed from NTLM authentication to Kerberos authentication, which is to address the issue with accessing companyweb.
Please check the followings:
Enable Negotiate (Kerberos) option for Sharepoint 3.0. To do this, follow these steps:
1. Click Start, click Administrative Tools, click SharePoint 3.0 Central Administration, and then click Continue in the User Access Control dialog box.
2. In the Authentication Providers page, click Application Management, and then click the “Authentication providers” on the Application Security tab.
3. Check the Web Application, make sure the port is 987; otherwise change Web application to the URL which has the port 987.
4. Click the “Default” zone, you will go to the Edit Authentication page.
5. Check the Negotiate(Kerberos) option on the Integrated Windows Authentication tab.
6. Click OK in the dialog which gives a warning that “You have chosed to use Kerberos with Integrated Windows authentication. Manual configuration steps by a domain administrator will be required if the application pool’s security account is not the Network Service” and then click Save.
Then access http://companyweb from the SBS2008 server itself and see if it works.
In addition, Windows 2008 SP2 and Vista SP2 has been released. Windows 2008 SP2 should be installed on SBS 2008. You can download the X64 version of SP2 here: http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=656c9d4a-55ec-4972-a0d7-b1a6fedf51a7 You should be sure to take a good backup prior to installing. SP2 will require a reboot so plan accordingly.