We want to observe outgoing email from Moodle. The following is my set up. Feel free to use a different setup if you want. Setup Create a docker instance for a mail server (Perhaps ask Raj for help if you have trouble). Edited: cleaning reference to outdated document – Create three users using the docker exec command mentioned in the above google doc, that will match a teacher and two students on your moodle site. You will need a teacher and two students on a Moodle site. Enrol only one of the students in a course (student1). Configure Thunderbird to recieve email from all three accounts (teacher and two students). Create a standard forum activity in the course. Set the subscription mode to "Forced subscription" so that everyone is subscribed. Probably a good idea to set the editing time for forum posts to 1 minute [Site administration  ► Security  ► Site policies] -> Maximum time to edit posts. Setup the mail server on Moodle. Go to [Site administration  ► Server  ► E-mail  ► Outgoing mail configuration  ► Email] -> SMTP hosts something like "mail.example.com" Add your email domain to allowed email domains "example.com" (Same page). Tests (outbound) Login is as the student1 and go to the preferences page (click the user menu in the top right corner and select preferences). Then select edit profile. Make sure that "Email display" is set to "Allow only other course members to see my email address". Add a post to the forum. Go to messages [User menu > Messages] , find the student who is not enrolled in the same course and send them a message, also send a message to the teacher. Log out and run the cron (cron is for sending messages for the forum). Check that emails are sent through. Have a look at the headers: The Return-Path information should have the address as noreply for all of the following checks of the email headers. For the email from student1 to the other student the "From" address should be from noreply. For the email from student1 to the teacher the "From" should include the email address. Log back in as student1. Change the setting for "Email display" to "Hide my email address from everyone". Add another post, and send a message again to the other student and teacher. Log out and run the cron. Check that emails are sent through. Have a look at the headers: All emails should have the from address of noreply. Log back in as student1. Change the setting for "Email display" to "Allow everyone to see my email address". Add another post, and send a message again to the other student and teacher. Log out and run the cron. Check that emails are sent through. Have a look at the headers: All emails should have the from address of the email address. Go to [Site administration  ► Server  ► E-mail  ► Outgoing mail configuration  ► Email] -> allowed email domains and delete all entries (and save). Log back in as student1. Add another post, and send a message again to the other student and teacher. Log out and run the cron. Check that emails are sent through. Have a look at the headers: All emails should have the from address of noreply. Tests (inbound) Go to [Site administration  ► Server  ► E-mail  ► Incoming mail configuration] and fill in all the fields on this page. (The information here doesn't have to be accurate. We won't actually be testing the forum reply by email feature). Go to [Site administration  ► Server  ► E-mail  ► message handlers] and change "Reply to forum posts" to Yes. Go to a forum that the users are subscribed to. Create a forum post and check "Send forum post notifications with no editing-time delay". Run the cron. Go to your email program and check the "reply-to" field. It should be something like {somename} +AAAAAIDDksjiJueks9@example.com Remove all of the domains from "Allowed email domains" and save. Go and send another forum post. Run the cron. Make sure that the "reply-to" field is still something similar to step 6.