ISAPI extensions and performance problems with NTLM authentication

I have developed an ISAPI extension that acts as a proxy for content
hosted by a a backend server. The idea is that the proxy (and IIS 6.0)
will handle authentication and then forward user identification to the
backend server. The proxy works fine when authentication is on. It also
works when Windows Integrated authentication is on, however performance
is impacted because connections between IE and IIS seem to be short
lived, which means that NTLM handshakes happen for pretty much every
request.


I came accross the following article which seems to be related:



http://groups-beta.google.com/group/...tnet.framework...
It indicates that in ASP.NET, one needs to set a property called
UnsafeAuthenticatedConnectionSharing to TRUE in order for connections
to persist.


Two questions:


1) Is there a similar problem/solution for ISAPI extensions?
2) If Kerberos authentication is used, does the problem go away?