> As far as your parenthetical example: it's not at all common or reasonable for a user to not configure their local-only mail server and then use it to send r

> As far as your parenthetical example: it's not at all common or reasonable for a user to not configure their local-only mail server and then use it to send remote mail. They'd use a properly configured remote server for that. I have no idea what makes you think that; you're probably coming from the Linux land where the mail command doesn't work by default? On non-Linux systems, local mail server is normally activated, and is fully capable of sending mail to the remote hosts by default, with a spool and all. The /usr/bin/mail just works, as well as sending mail from anything like mutt and friends, without any configuration (other than specifying an outgoing FROM hostname to not a non-existent one). Unless the outgoing SMTP port is blocked — which it's not on many networks for advanced users — there's nothing to configure.