Hello!
I wrote a while back about my new architecture for the vKaiser.com site. I have been relatively happy with the setup until I realized one thing about the system. If I have three frontend servers with Drupal installed in all of them, all of them should be capable of sending email. I had only configured the first one which I have been happy with as it powers the dkaiser.com mail traffic (which is not much to be honest) as well.
So I now had to try to remember what I had done about a year ago with Postfix to get it running the first place. I used a rather old image to build the two other servers which did not even have it installed, only FFMPEG which by the way works pretty well in this kind of distributed system. I had done something with the /etc/postfix/main.cf as I had configured AuthSMTP to work as the relay agent. I found some decent instructions from here which I pretty much followed, while also copying the main.cf from the working server. Those instructions are really spot on, except I had to do postmap /etc/postfix/canonical to actually build the canonical.db, but after that mail started working. By default the sender is apache@example.com which if you haven’t allowed in AuthSMTP won’t get too far.
Now all is good!
