Slow Performance With IIS Basic Authentication


I'm using SSAS through HTTP with MSMDPUMP.dll. I have setup the MSMDPUMP.dll web to use only Basic Authentication and then I provide the User Id and Password in the ConnectionString. Everything works but it's too slow to be usable. I have enabled Failed Request Tracing in IIS and I have noticed that I get thousands 401.2 errors with the following information:

ModuleName IIS Web Core
Notification 2
HttpStatus 401
HttpReason Unauthorized
HttpSubStatus 2
ErrorCode 2147942405
ErrorCode Access is denied. (0x80070005)

I believe this is the overhead and the reason why it is slow? If I change the authentication to Anonymous, everything works fast. Unfortunately this is not an option so I need to resolve this issue with Basic Authentication performance. Any ideas?

EDIT It seems that it tries first Anonymous auth and only after failing goes with basic. I don't have anonymous auth even enabled so I don't know why this is happening.

asked on Server Fault Oct 9, 2012 by Antti Simonen • edited Oct 9, 2012 by Antti Simonen

1 Answer


If the service access performs many requests, and each request has to be authenticated, this would be the expected behavior if an authentication cookie is not set. If every request has to perform a full authentication, performance will be noticeably degraded.

If you are unable to set an auth cookie, and you can use Windows authentication, IIS has a setting to only authenticate the first request.

You may experience slow performance when you use Integrated Windows authentication together with the Kerberos authentication protocol in IIS 7.0

answered on Server Fault Oct 9, 2012 by Greg Askew • edited May 23, 2017 by Community

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