Ken Wright: > > There are many other possibilities.? Perhaps, instead of doing all > > the integration work yourself, you may be better off with a "turnkey" > > email server such as <https://mailinabox.email>? > > If I don't do the work, how will I learn?
You learn by starting with a WORKING system, then making small changes and verifying after each change that the system still works, before making the next change. Postfix works out of the box: it receives mail on port 25 and with /usr/sbin/sendmail, and it delivers mail to the system mailbox directory. All further changes should be made one at a time, instead of making all changes an once and then trying to figure out what is broken. Wietse