IIS Windows Authentication not working in Internet Explorer via host name; works via IP
Need to set the SPN?
http://technet.microsoft.com/en-us/library/cc772897(WS.10).aspx
I hope this article helps you set NTLM as the primary authentication method.
http://support.microsoft.com/kb/215383
In many cases I was never able to get kerberos authentication working correctly. If you wish to further troubleshoot kerberos try using kerbtray on the client computer.
http://www.microsoft.com/downloads/en/details.aspx?familyid=4E3A58BE-29F6-49F6-85BE-E866AF8E7A88&displaylang=en
This also may help: http://support.microsoft.com/kb/299838