iis7设置404页面不生效的原因

打开web.config

<httpErrors errorMode="Custom" existingResponse="PassThrough">
            <remove statusCode="404" subStatusCode="-1" />
            <error statusCode="404" prefixLanguageFilePath="" path="/404.html" responseMode="ExecuteURL" /></httpErrors>
    </system.webServer>

去掉httpErrors的属性

 existingResponse="PassThrough"

即可