You have qmail set up and running on your machine.

Show that you can send and receive mail of various sorts: user-sameuser local, user-othreuse local, user-remote, remote-user, and so on.

Follow headers as we have discussed to make sure you understand them.

Especially nice homework will find situations in which there is more than one forwarder for the email and track the headers. A very instructive setting is when there are multiple time zones involved.