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IIS log show cs-username is blank and sc-status is 401 RRS feed

  • Question

  • In IIS log there is a large number of rows showing cs-username is blank and sc-status is 401. Where is it coming from and how to check it? I have a LB using layer7 which changes client IP to LB IP. So I can't tell from cs-client IP to identify where is it from. Any suggestion is appreciated.
    Friday, December 29, 2017 1:11 AM

Answers

  • Hi,

    Thanks for contacting our forum. Could you please show us the detailed IIS log with the error codes?

    401 means Access denied, with the following different reasons:

    401.1 - Logon failed.

    401.2 - Logon failed due to server configuration.

    401.3 - Unauthorized due to ACL on resource.

    401.4 - Authorization failed by filter.

    401.5 - Authorization failed by ISAPI/CGI application.

    Please also refer to: https://blogs.msdn.microsoft.com/david.wang/2005/07/15/howto-diagnose-401-x-http-errors-on-iis/  for troubleshooting steps.

    Hope it helps.

    Regards,

    Jason Chao


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

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    • Proposed as answer by Jason.Chao Tuesday, January 2, 2018 9:44 AM
    • Marked as answer by AlanG2015 Friday, January 5, 2018 9:08 PM
    Monday, January 1, 2018 4:17 AM

All replies

  • Hi,

    Thanks for contacting our forum. Could you please show us the detailed IIS log with the error codes?

    401 means Access denied, with the following different reasons:

    401.1 - Logon failed.

    401.2 - Logon failed due to server configuration.

    401.3 - Unauthorized due to ACL on resource.

    401.4 - Authorization failed by filter.

    401.5 - Authorization failed by ISAPI/CGI application.

    Please also refer to: https://blogs.msdn.microsoft.com/david.wang/2005/07/15/howto-diagnose-401-x-http-errors-on-iis/  for troubleshooting steps.

    Hope it helps.

    Regards,

    Jason Chao


    Please remember to mark the replies as answers if they helped. If you have feedback for TechNet Subscriber Support, contact tnsf@microsoft.com.

    Click here to learn more. Visit the dedicated forum to share, explore and talk to experts about Microsoft Teams.

    • Proposed as answer by Jason.Chao Tuesday, January 2, 2018 9:44 AM
    • Marked as answer by AlanG2015 Friday, January 5, 2018 9:08 PM
    Monday, January 1, 2018 4:17 AM
  • Hi, I have the same issue, the IIS logs contain lots of 401.1 and 401.2 and for these entries cs-username is blank. For other entries for 404, 415, 200, the cs-username is present. Can you please let me know why the entries are blank only for 401.1 and 401.2?
    Thursday, April 12, 2018 8:32 AM