I am using Apache in a reverse proxy setup with something like: ProxyPass /app http://internal.com/app ProxyPassReverse /app http://internal.com/app This works fine except the internal application has some css/xs/xml content that is referencing the internal URL and this causes some of the page content to fail to render. The data I am trying to manipulate is being returned as: Location: http://external.com/app/?xmlURL=Internal.com/app/somecontent I need the xmlURL to be modified by the Apache web server to be the external URL. I am using Apache 2.2. I have tried mod_substitute without any success. Any help would be greatly appreciated!