I just redid a site and it went live this past weekend. The client is concerned because Google (and other search engines) have all their old pages indexed. When you click a link from Google it says Page can not be displayed.

All the pages end with .cmf (ColdFusion) from the old site that are indexed. If your remove the .cmf the page then goes to the custom 404 page created by AceSEF.

My question is how would I make any page that is indexed by search engines that end with .cmf go to the custome 404 page?

You should add the .cmf to your .htaccess file like this:

Thank you Denis.