<configuration>

    <system.webServer>

      <rewrite>

          <rules>

        <rule name="bbs board" enabled="true">

            <match url="^forum_([0-9]+)\.htm$" />

            <action type="Rewrite" url="/list/{R:1}" />

        </rule>

       </rules>

      </rewrite>

   </system.webServer>

</configuration>