We have a public web server eg www.johnsmith.com that uses Apache.
It has an internal IP address and an external IP address.
We also have a server hosting Piwik but this only in the internal LAN.
Apache httpd.conf has a redirect in this setting.
Is it possible, then, for some one to make a HTTP request in his browser to retrieve the page from the web server . Web server switches page to piwik server which is internal.