We use piwik behind a reverse proxy and as generating the tracking code the server shows the intranet view like this: //piwik.mydomain.de/piwik/

  (function() {
    var u="//piwik.mydomain.de/piwik/";
    _paq.push(['setTrackerUrl', u+'piwik.php']);

The internet view instead is: //www.mydomain.de/piwik/

Thus it would be nice if I could set a u-variable on the page where the tracking code is generated and that value overrides the system generated value u.

A variable in config/config.ini.php would good a well. Adding this pice of information at FAQ: "Using piwik behind a proxy" would be nice.

Same as tracking image...