i want to be able to send mail to someuser@localhost but not allow any mail to go out to the outside world from anyone to anyone. i've seen multiple entries about how to filter or restrict outgoing mail, but it seems like there should be a simpler way to just turn it off.
i would like to still be able to use something like PHPMailer to explicitly log in to an outside SMTP server and send mail that way, though. i don't know if these goals are compatible or not. i am pretty sure that this is how it used to work when i was running Ubuntu 9.04. i've upgraded to 11.04 and now mail will go out to any address without a problem.