ASP.NET forms-based authentication
(FBA) is currently a popular choice for
extranet solutions in SharePoint. However,
implementing FBA isn’t one of the more
pleasant experiences in SharePoint. It
requires hand-editing the web.config file
and doesn’t have much of a UI in the Central
Administration console for configuration.
Furthermore, rich client integration
features are affected a bit. In Central
Administration, when you assign your
web application to use an FBA provider,
the Enable Client Integration check box
is cleared by default. This is SharePoint’s
way of warning you about some future
potential problems. If client integration is
turned on for FBA, Microsoft claims that
most Office integration features should
work, but that they need to be thoroughly
tested first. You can find FBA client
integration workarounds and tricks on
the web, and some are even hosted on
CodePlex, but Microsoft doesn’t support
them. Finally, keep in mind that using FBA
requires purchasing an external connector
license, which will increase the total
solution cost. My general recommendation
regarding FBA is to try to avoid it
if possible, or follow the advice in the
MSDN article “Forms Authentication in
SharePoint Products and Technologies
(Part 1): Introduction” at msdn.microsoft.com/en-us/library/bb975136.aspx, which
states, “Before using forms authentication,
determine why to use forms authentication
in the first place: What is the business
driver?”