mod_rewrite is enabled on the server.
What are the typical problems that mod_rewrite can help you with:
Your pages have moved to a new address and you want them to redirect visitors.
Your pages have complicated addresses. You can not remember them, it is difficult to send them by e-mail, they do not express the content of the site or the structure of the web.
SEO Optimalization of URLs for search engines. (instead of: idclanku = 4529, for example: / profi-hosting)
Dynamic pages contain parameters in URLs and search is reluctantly index.
You want to make website addresses that are independent of the technology used, and then you need to get rid of terminals html, php, etc.
Risk arising from erroneously used mod_rewrite in. Htaccess:
Incorrectly crafted file. Htaccess can lead to the closure of your website.
Wrong. Htaccess can wrap.
Example. Htaccess. Redirect all addresses in index.php and a 404 error:
RewriteEngine On
RewriteBase /

ErrorDocument 404 /

RewriteCond% {REQUEST_URI}! \. ([A-z] +) $
RewriteCond% {REQUEST_URI}! / $
RewriteRule ^ (. * [^ /]) $ $ 1 / [R = 301, L]

RewriteRule ^ ([^.] *) $ Index.php [L]
Interesting information about mod_rewrite can also be found

php_value parameters are not available in fcgid mode and when used in the file. htaccess can cause malfunctions pages.