Modify the Default URLScan Configuration File

Paste the Urlscan folder in the %Windir%\System32\Inetsrv directory. Double-click the Urlscan folder under Inetsrv, and then open Urlscan.ini in Notepad.

In the Urlscan.ini file, be sure to enable UseAllowExtensions, as follows:
UseAllowExtensions=1; if 1, use [AllowExtensions] section, else

Urlscan allows you to specify a null extension in the [AllowExtensions] section. To do this, add a period (.) in the [AllowExtensions] section, as follows:
; Extensions listed here are commonly used on a typical IIS server.
; Note that these entries are effective if \"UseAllowExtensions=1\"
; is set in the [Option] section above.