Prevent url with a directory from pointing to a web page

I have a domain let's call it newsite.com which is parked to maindomain.com. I use mod-rewrite to direct all requests for newsite.com to a subdirectory on maindomain.com. On newsite.com I have CodeIgniter installed. Which means the urls look like this:

newsite.com/products/shoes/

The above works just fine.

However, if I set up a controller for a page like this:

newsite.com/about/ or newsite.com/about/faqs/

I get a 404 which I believe is being caused because it is looking for the page maindomain.com/about.php which does exist, but does NOT exist on newsite.com.

My question is.... how do I PREVENT urls like newsite.com/about/ from pointing to newsite.com/about.php ? This is the opposite of what many people try to do (they tend to want to allo开发者_高级运维w the file extension to be missing).

I'm wondering if it is and apache or PHP setting that causes it to look for the file first if it exists and the directory does not? Or do I need to add more mod-rewrite rules?

Thanks very much!

Edit - here is my .htaccess file currently. It resides at the web root of the maindomain.com shared hosting account.

# Redirect various urls to subfolders of the format: /site-thename/

RewriteEngine On

# Remove the www for NewSite.
RewriteCond %{HTTP_HOST} ^www.newsite.com$ [NC]
RewriteRule ^(.*)$ http://newsite.com/$1 [R=301,L]

# Handle pages and directories that should not go through CodeIgniter.
RewriteCond %{HTTP_HOST} ^(www\.)?newsite\.com
RewriteCond %{REQUEST_URI} !^/site-newsite/
RewriteCond %{REQUEST_URI} ^/demo/ [OR]
RewriteCond %{REQUEST_URI} ^/robots\.txt [OR]
RewriteCond %{REQUEST_URI} ^/emailform\.php [OR]
RewriteCond %{REQUEST_URI} ^/assets/ [OR]
RewriteCond %{REQUEST_URI} ^/index\.php
Rewriterule ^(.*)$ /site-newsite/$1 [L]


# Handle CodeIgniter URLs.
RewriteCond %{HTTP_HOST} ^(www\.)?newsite\.com
RewriteCond %{REQUEST_URI} !^/site-newsite/
Rewriterule ^(.*)$ /site-newsite/index.php?/$1 [L]

---

Asked my hosting company's support department what might be causing this... and it turns out that it is caused by Apache MultiViews. This can be turned off via

Options -MultiViews

in the htaccess file. That worked. Thanks for the suggestions.

---

If you have no rewrite rules for it, Apache, by default, will reference whatever is on the filesystem. You must have rewrite rules there to tell Apache to use a specific controller to handle requests instead of attempting to reference objects on the filesystem.

---

I assume that if you are an apache user, you use .htaccess file for redirecting the URL to you 'index' file (let's call it index.php). Also you should have sth like:

RewriteEngine on
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule .* index.php

in your .htaccess file. Note that the RewriteCond condition has a parameter which checks if it is not a file:-) More can be found at http://httpd.apache.org/docs/2.0/mod/mod_rewrite.html#rewritecond