SUMMARY
Windows SharePoint Services does not support forms-based
authentication. You cannot implement forms-based authentication for Windows
SharePoint Services Web sites.
Forms-based authentication was not implemented in SharePoint. Attempts to use forms-based authentication will result in many problems. A common example is that search crawling will fail in Microsoft Office SharePoint Portal Server 2003. Additionally, you will an error message that resembles the following:
The address could not be found, (0x80041204 - An unrecognized HTTP status was received. Check that the address can be accessed using Internet Explorer. )
In this scenario, the provider implements its security by using browser cookies. The SharePoint search crawler is unable to correctly authenticate when cookie-based authentication systems are used.
There are many other problems that will occur with forms-based authentication. This article does not describe these problems largely because the scenarios are untested becuase they are not supported.
In order to address this common feature request, SharePoint is providing support for forms-based authentication in Microsoft Office Server 2007 and in Windows SharePoint Services (version 3).