I have a DNS wildcard setup, so any subdomain gets redirected to my main domain.

I am looking to change each subdomain to index.php?subdomain= and am using mod_rewrite for that. It should happen with all domains except for www and images.

I have the below code, but well, it isnt working. Not giving any errors, but just not rewriting anything

RewriteEngine On
RewriteCond %{HTTP_HOST} !^(www|images)\.cpabux\.com$
RewriteRule ^(.*).cpabux.com$ cpabux.com/index.php?subdomain=$1
any help would be greatly appreciated