重写规则为codeIgniter不工作

我已经安装了一个干净的Apache2（加上PHP和放大器; MySQL的）服务器，并启用的mod_rewrite 在Apache的配置。
我加了的.htaccess 文件从作为codeIgniter维基描述的URL删除的index.php。

I have installed a clean Apache2 (plus PHP & MySQL) server and enabled the mod_rewrite in the apache config. I added the .htaccess file to remove the index.php from the url as described in the CodeIgniter wiki.

RewriteEngine on
RewriteCond $1 !^(index\.php|images|robots\.txt)
RewriteRule ^(.*)$ /index.php/$1 [L]

我放置在网站的根文件。

I placed this file in the website's root.

当我尝试访问该网址 mydomain.local / index.php文件/欢迎然后我得到codeIgniter的默认页面。但是，当我试图通过 mydomain.local /欢迎访问同一页面然后我得到了404页。

When I try to access the url mydomain.local/index.php/welcome then I get the default page of CodeIgniter. But when I try to access the same page through mydomain.local/welcome then I get the 404 page.

我如何检查，如果整个重写规则是否有效？而为什么不工作？

How can I check if the whole rewrite rule is working? And why isn't it working?