Getting 404.7 error for “/” root requests after Disabling Allow Unlisted file extension

by jask2002 7. March 2013 12:05

To secure the IIS 7.x one of the recommendation is to change the Request Filtering => FIle Extensions: To Allow only the  known extensions.

For example : Default values in IIS 7.x Request Filtering => File Name Extension on IIS



Ideally it should be (ONLY needed and known extensions Allowed)

Tip: Instead of deleting Each and every entry manually. You can use <clear /> in web.config . Then add entries from IIS UI

                             <clear />




To get the list of extension needed by your application you can parse your website IIS log

C:\Program Files (x86)\Log Parser 2.2>Logparser "SELECT EXTRACT_EXTENSION(cs-uri-stem) As Extension FROM 'ex130309.log' GROUP BY Extension" -o:datagrid -i:W3C

Now we will Uncheck the “Allow unknown File Extensions” in Edit Feature Settings in Request Filtering Action Pane so that IIS should only honor the above listed extensions




Here the actual problem started upon browsing http://localhost/ I got IIS error 404.7 but IF I browse http://locahost/iisstart.htm everything works!

(404.7 means File extension denied by Request Filtering ) Well I’m browsing without extension to the root  “/”. To fix this nuisance

Add an allowed Entry for “.”  Dot without Quotes



Happy to Securing IIS Smile

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