│ Internet site using smarthost - You receive Internet mail on this         ▒
 │ machine, either directly by SMTP or by running a utility such as          ▒
 │ fetchmail. Outgoing mail is sent using a smarthost. optionally with       ▒
 │ addresses rewritten. This is probably what you want for a dialup system.  ▒
 │                                                                           ▒
 │ Satellite system - All mail is sent to another machine, called a "smart   ▒
 │ host" for delivery.  No mail is received locally.                         ▒