404 file not found，那就是rewrite的rules配的有問題，這裏有篇官方文檔，讀完了就不會犯這種錯啦。

https://docs.microsoft.com/en-us/iis/extensions/url-rewrite-module/url-rewrite-module-configuration-reference

500 server internal error，這個其實一般用ASP.NET才會遇到，尤其是MVC。。因為@Html.ActionLink之類的函數，在渲染的時候會和url rewrite沖突，報錯為：

Cannot use a leading .. to exit above the top directory.

解決方法也很簡單，把類似的函數用html重寫下就行了，比如

<li>@Html.ActionLink("Home", "Index", "Home")</li>

=>

<a href="/Home/Index" class="navbar-brand">Home</a>

還有種情況就是rewrite成功，返回了200，但是卻不是自己想要的結果，如果不能正向找到問題，那就把這段配置加到system.webServer節點中去，抓去所有返回200-299的訪問，然後訪問下網頁，再看看生成W3SVC的日誌。日誌生成後，記得把這段配置刪了，不然會非常卡，原因你懂的。

<tracing>
  <traceFailedRequests>
    <remove path="*" />
    <add path="*">
      <traceAreas>
        <add provider="ASP" verbosity="Verbose" />
        <add provider="ASPNET" areas="Infrastructure,Module,Page,AppServices" verbosity="Verbose" />
        <
 
add provider="ISAPI Extension" verbosity="Verbose" />
        <add provider="WWW Server" areas="Rewrite,RequestRouting,Authentication,Security,Filter,StaticFile,CGI,Compression,Cache,RequestNotifications,Module,FastCGI"
       verbosity="Verbose" />
      </traceAreas>
      <failureDefinitions statusCodes="200-299" />
    </add>
  </traceFailedRequests>
</tracing>

下面再來一個抓訪問慢的請求發生時的dump文件的配置

<tracing>
     <traceFailedRequests>
     　　<remove path="*" />
     　　<add path="*" customActionExe="d:\home\site\Diagnostics\procdump.exe" customActionParams="-ma -accepteula %1% d:\home\site\Diagnostics\w3wp_PID_%1%_" customActionTriggerLimit="5"> 
           　　<traceAreas>
                 　　<add provider="ASP" verbosity="Verbose" />
                 　　<add provider="ASPNET" areas="Infrastructure,Module,Page,AppServices" verbosity="Verbose" />
                 　　<add provider="ISAPI Extension" verbosity="Verbose" />
                 　　<add provider="WWW Server" areas="Authentication,Security,Filter,StaticFile,CGI,Compression,Cache,RequestNotifications,Module,FastCGI" verbosity="Verbose" />
           　　</traceAreas>
           　　<failureDefinitions timeTaken="00:00:30"  />
     　　</add>
     </traceFailedRequests></tracing>

@Html.ActionLink

URL Rewrite 導致404,500錯誤