Kerberos is the widely deployed authentication protocol. This paper gives the user comparison between NTLM and Kerberos authentication. And it gives information on how Kerberos authentication plays a vital role in authentication and delegation scenarios, and the situations where Kerberos authentication should be used or may be required in solution designs. Scenarios include business intelligence implementations which secure access to external data sources such as SQL server. The paper also shows how to configure Kerberos authentication end-to-end within the users' environment, including scenarios that use various service applications in Microsoft SharePoint server.