IIS 7 and Above
IIS 7.5 Intermittent 401 Error When App Pool Initializes
Last post Jan 14, 2012 02:35 PM by HCamper
Jan 09, 2012 08:07 PM|sjfozz|LINK
We are using IIS 7.5 with Kerberos authentication. When a .NET app pool is accessed and needs to be initialized or started up, the browser receives a log-in prompt. The user can simply cancel from the prompt and receive the 401 error. However, they can click
on the same link again and they will receive no prompt once the app pool is started up. Traces with Fiddler do not show anything unusual. As mentioned before, things are fine as long as app pools are started up.
Below is some information about the environment:
Below is some additional info I have found with further experimentation:
Jan 14, 2012 02:35 PM|HCamper|LINK
Sorry for the late reply.
Thanks for the information:
IIS 7.5 with Windows Server 2008 R2 Standard Kerberos authentication "Double Hop Issue" maybe
one of many (Google or Bing) for others.
The browser and user receives a log-in prompt add the Web Site in IE to the Trusted Zone .
Traces with Fiddler do not show "The user can simply canceled a certificate Warning"
Check the IIS Server log "user can simply cancel from the prompt and receive the 401 error"
Trouble Shooting 401 errors http://support.microsoft.com/kb/907273 .
The problems with ApplicationPoolIdentity in the application pool.
Just a guess you have used IIS 6.0 Server before
You may find FRT
http://learn.iis.net/page.aspx/266/troubleshooting-failed-requests-using-tracing-in-iis/ will help in
Feel free to post the IIS Server log Status codes for checking.
References: Security http://learn.iis.net/page.aspx/139/iis7-and-above-security-improvements/
http://learn.iis.net/page.aspx/140/understanding-built-in-user-and-group-accounts-in-iis/ Accounts & Users.