Insert the following snippet in the <configuration>
element.
<location path="Default Web Site/ias_relay_server/client">
<system.webServer>
<handlers accessPolicy="Execute, Script">
</handlers>
</system.webServer>
</location>
<location path="Default Web Site/ias_relay_server/server">
<system.webServer>
<handlers accessPolicy="Execute, Script">
</handlers>
</system.webServer>
</location>
<location path="Default Web Site/ias_relay_server">
<system.webServer>
<security>
<authentication>
<anonymousAuthentication userName="" />
</authentication>
<requestFiltering>
<requestLimits maxAllowedContentLength="2147483647" />
</requestFiltering>
</security>
</system.webServer>
</location>