Re: 401 - Error from WebServer

From: Chris (
Date: 10/09/02

From: ("Chris")
Date: Wed, 09 Oct 2002 20:10:27 GMT

This is normal if you have anonymous authentication disabled and are using
Basic and\or NTLM. The authentication handshake assumes anonymous first
(no matter the setting) and the browser depends on IIS to respond with the
correct WWW-Authenticate header.

If anonymous is disabled, IIS will send in the header the correct methods
to use like Basic, Negotiate (for Kerberos), or NTLM for NTLM. With that
said, you should always see a 401.1 Login Failed in your logs for any
content that is not using anonymous and then a subsequent authenticated log
entry with the username. This is all by design.

Here is the article that discusses this...

Q264921 INFO: How IIS Authenticates Browser Clients;EN-US;Q264921


Microsoft IIS Technical Lead

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