title: IIS7, SSL and "The page was not displayed because the request entity is too large."
body: <p>We're running an ASP.NET application over SSL on IIS7 on a 64-bit machine.</p>
  
  <p>Now I've found several articles mentioning that to resolve this error, I need to modify the <code>system.webServer/serverRuntime/uploadReadAheadSize</code>. Fine. I tried via <code>appcmd.exe</code> and then just manually editing my web.config to set this:
        
          
  
  <pre><code>    other config settings
  
      --&gt;
      &lt;serverRuntime uploadReadAheadSize="1048576" /&gt;
    &lt;/system.webServer&gt;
  </code></pre>
  
  <p>However, when I set this in the site's web.config, I get this error:</p>
  
  <blockquote>
    <p>This configuration section cannot be used at this path. This happens when the section is locked at a parent level. Locking is either by default (overrideModeDefault="Deny"), or set explicitly by a location tag with overrideMode="Deny" or the legacy allowOverride="false".</p>
  </blockquote>
  
  <p>From there, I Googled and posts said that this config section needs to be unlocked. So I ran appcmd.exe to unlock it, but I get an error from appcmd.exe:</p>
  
  <blockquote>
    <p>C:\Windows\System32\inetsrv>appcmd.exe set config -section:system.webserver/serverruntime/uploadreadaheadsize:1048576 /commit:apphost ERROR (message:Unknown config section "system.webserver/serverruntime/uploadreadaheadsize:1048576".  Replace with ? for help. )</p>
  </blockquote>
  
  <p>I got it opened in notepad 64-bit and modified it:</p>
  
  <pre><code>&lt;section name="serverRuntime" overrideModeDefault="Allow" /&gt;
  </code></pre>
  
  <p>First off, is it wise to allow this to be overidden? If not, what are the alternatives? If it is overridden what are the potential issues with setting this in my web.config so that the uploadreadaheadsize is larger than the default? One site mentioned the potential for a DoS attack.</p>