I've been trying to configure the mail() function for 3 days by now, and I'm running out of ideas.

I've installed and configured postfix as a satellite, following this guide: How to have my PHP Send mail? but it seems I lack the file /etc/postfix/sender_canonical (and of course I have no idea of what to put inside it). By now this is the only clue I have about the problem...

I'm trying to run it on Ubuntu 12.04 laptop, built with x32 architecture.

EDIT: After a few iterations of apt-get purge and apt-get install, mail() started to return true, the error log has stopped growing so it seems all ok, but no mail managed to reach my inbox, not even as spam.