Ok I see so they are defaulted, just wanted to be sure, so I installed roundcube on the mail server which responds to internal ip of 192.168.0.10/roundcube but it doesnt respond to the hostname of mail.example.com
I made these changes in ispconfig on the cpanel server: (ubuntu)
isset($_SERVER['HTTPS'])? $http = 'https' : $http = 'http';
$http = 'http';
header('Location:' . $http . '://' . $serverData['server_name'] . '/roundcube');
now it redirects properly but doesn't pull up roundcube, rather I get page not found error.