Our SMTP for Kayako isn't working. Under Admin CP > Settings > Email Settings, there's an option called Enable SMTP, and it's desription says, "Select whether an SMTP server should be used to send email. By default, Resolve will use the internal PHP mail() function to send email". I understand that if I disable this option, it should use the PHP Mail function instead. But then how do I get PHP mail set-up? Am on Ubuntu 10.04 self-hosted Kayako.