I've worked my way through most of Lynn's excellent book and have successfully set up two Drupal sites, a local one on my laptop and another one on my personal website at fusiontrek.com

When I setup my local (development) Drupal site on my laptop it came as no surprise that there was no support for sending email. I think I did install Mercury as part of the XAMPP setup on my laptop, but even with Mercury installed the site on my laptop still couldn't send/receive email. And that made perfect sense to me because to send email there needs to be an internet-connected email server available to Drupal.

However, what puzzles me is how can Drupal send email on my public site without any problem when I never specified an SMTP mail server during the Drupal setup and configuration process? Does Drupal test for the presence of an SMTP server during setup and automatically configure it? If not, then how can Drupal send out emails from my site? It seems to me that Drupal must be using my web host's email server, but I don't understand how it acquired the correct mail server settings and auto-configured itself...