DOCUMENT:Q155253 29-APR-1999 [iis] TITLE :Improper NTFS Permissions May Result in IIS Failure PRODUCT :Internet Information Server PROD/VER:1.0 2.0 3.0 OPER/SYS: KEYWORDS:kbnetwork ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Internet Information Server versions 1.0, 2.0, 3.0 ------------------------------------------------------------------------------- SUMMARY ======= Improper modification of Microsoft Windows NT file system (NTFS) permissions may create an environment where browser clients fail when attempting to access the Microsoft Internet Information Server (IIS) publication services. MORE INFORMATION ================ Microsoft Windows NT version 4.0 installs on a new NTFS partition with change permission for the group Everyone. Improper NTFS access permissions involving other Windows NT accounts such as System, Network, Interactive, and IUSR_ComputerName may affect the operation of IIS. Most of these improperly defined permissions result in a browser client receiving an HTTP response of 401 Access Denied. As an example, consider an IIS server that has been configured with only Allow Anonymous access in the in WWW Services tab of the Internet Service Manager. The web master has set the following permissions on his or her NTFS WWW publication directory wwwroot of: CREATOR OWNER Full Control ComputerName\Administrators Full Control IUSR_ComputerName Full Control Everyone No Access System Full Control The web master calls Microsoft Product Support, describing an issue in which no one can access his or her IIS server from a WWW client browser. A sniffer trace shows that all of the client browsers receive a 401 Access Denied error message in the HTTP response. The problem is the NTFS permissions. The Web master has allowed the IIS anonymous user account IUSR_ComputerName full access, but the web master has also explicitly denied the group Everyone. The IUSR_ComputerName account belongs to the group Everyone. An explicit deny always takes precedence over an allow, therefore no browser client can access the IIS server. Before contacting Microsoft Product Support Services, customers are encouraged to check the NTFS permissions to verify that any modified access permission is not the cause of improper IIS functionality. For more information on issues related to NTFS permission, please see the following articles in the Microsoft Knowledge Base: Q109076 : Removing Permissions to an NTFS Partition May Prevent Startup Q130016 : Removing Everyone On Root Dir. Leaves Limited Virtual Memory Q137155 : Users Without System32 Permissions Cannot Log On Q137400 : Changing Default Permissions Causes STOP 0xC000021A Q138923 : Partitions Displaying as Unknown in Disk Administrator Additional query words: prodiis ====================================================================== Keywords : kbnetwork Technology : kbiisSearch kbiis300 kbiis200 kbiis100 Version : 1.0 2.0 3.0 Issue type : kbhowto ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1999.