I believe that's a config option dependent upon whether you specify an SMTP server.
If you don't it uses mail()
Pierre Mauduit wrote:
hi,
and try to check if the PHP mail() function (http://php.net/mail for more info) is working correctly, by using a little script like :
[...]
In fact this test is useless, since Roundcube seems to use PEAR classes with sockets in order to communicate with SMTP servers, and not the php mail() function. Sorry for replying a bit too fast.