It is possible to configure your website in Matomo (Piwik) so that only requests to “example.com” will be tracked, and all other requests ignored. Go to Administration > Websites > click “Edit”. Below the “URLs” field for your website, there is a checkbox “Only track visits and actions when the action URL starts with one of the above URLs.”. If you click this checkbox, and click “Save”, Matomo will then only track requests where the domain and the path is an exact match of one of the URLs you specified for this website. This means each valid subdomain has to be specified separately. For example when the known URLs are ‘http://example.com/path’ and ‘http://good.example.com’, tracking requests for ‘http://example.com/otherpath’ and ‘http://bad.example.com’ are ignored.