What do these rewrite rules mean?

I subscribed to voltrank (website for building backlinks) and they told me to modify the .htaccess file with开发者_开发知识库 the following text:

RewriteEngine On
RewriteRule ^$ /vr_display_50727b.php?filename=index.html [L,NC]
RewriteRule ^(.*)\.html$ /vr_display_50727b.php?filename=$1.html [L,NC]
RewriteRule ^(.*)\.htm$ /vr_display_50727b.php?filename=$1.htm [L,NC]

My Question is: Is this safe and what does it mean? My main concern is security. By the way, after modifying the .htaccess file, my stats showed that two offensive IP addresses had accessed my website. I'm not sure if the modification has anything to do with this or it is just coincident. Thanks

It's a coincidence. What this does is cause all requests to execute vs_display_50727b.php instead.

What you should be concerned about is having your search ranks go down instead of up by using this program. Google does not like services designed to manipulate its rankings.

This is completely safe as it seems that your system is a kind of CMS which takes filenames as parameter to display the corresponding content. All this is redirecting your requests to vr_display_50727b.php page which decides which content will be drawn on page and same time helps you to have fancy URL with secure HTM /HTML filenames.

These rewrite rules increase page ranking