This document will take you through the steps of setting up a basic Postfix mail server with IMAP authentication on Ubuntu, to be used with Reply by email.
The instructions make the assumption that you will be using the email address [email protected]
, that is, username incoming
on host gitlab.example.com
. Don't forget to change it to your actual host when executing the example code snippets.
- Open up port 25 on your server so that people can send email into the server over SMTP.
- If the mail server is different from the server running GitLab, open up port 143 on your server so that GitLab can read email from the server over IMAP.
-
Install the
postfix
package if it is not installed already:sudo apt-get install postfix
When asked about the environment, select 'Internet Site'. When asked to confirm the hostname, make sure it matches
gitlab.example.com
. -
Install the
mailutils
package.sudo apt-get install mailutils
-
Create a user for incoming email.
sudo useradd -m -s /bin/bash incoming
-
Set a password for this user.
sudo passwd incoming
Be sure not to forget this, you'll need it later.
-
Connect to the local SMTP server:
telnet localhost 25
You should see a prompt like this:
Trying 127.0.0.1... Connected to localhost. Escape character is '^]'. 220 gitlab.example.com ESMTP Postfix (Ubuntu)
If you get a
Connection refused
error instead, verify thatpostfix
is running:sudo postfix status
If it is not, start it:
sudo postfix start
-
Send the new
incoming
user a dummy email to test SMTP, by entering the following into the SMTP prompt:ehlo localhost mail from: root@localhost rcpt to: incoming@localhost data Subject: Re: Some issue Sounds good! . quit
Note: The
.
is a literal period on its own line.Note: If you receive an error after entering
rcpt to: incoming@localhost
then your Postfixmy_network
configuration is not correct. The error will say 'Temporary lookup failure'. See Configure Postfix to receive email from the Internet. -
Check if the
incoming
user received the email:su - incoming mail
You should see output like this:
"/var/mail/incoming": 1 message 1 unread >U 1 root@localhost 59/2842 Re: Some issue
Quit the mail app:
q
-
Log out of the
incoming
account and go back to beingroot
:logout
Courier, which we will install later to add IMAP authentication, requires mailboxes to have the Maildir format, rather than mbox.
-
Configure Postfix to use Maildir-style mailboxes:
sudo postconf -e "home_mailbox = Maildir/"
-
Restart Postfix:
sudo /etc/init.d/postfix restart
-
Test the new setup:
-
Follow steps 1 and 2 of Test the out-of-the-box setup.
-
Check if the
incoming
user received the email:su - incoming MAIL=/home/incoming/Maildir mail
You should see output like this:
"/home/incoming/Maildir": 1 message 1 unread >U 1 root@localhost 59/2842 Re: Some issue
Quit the mail app:
q
Note: If
mail
returns an errorMaildir: Is a directory
then your version ofmail
doesn't support Maildir style mailboxes. Installheirloom-mailx
by runningsudo apt-get install heirloom-mailx
. Then, try the above steps again, substitutingheirloom-mailx
for themail
command. -
-
Log out of the
incoming
account and go back to beingroot
:logout
-
Install the
courier-imap
package:sudo apt-get install courier-imap
-
Let Postfix know about the domains that it should consider local:
sudo postconf -e "mydestination = gitlab.example.com, localhost.localdomain, localhost"
-
Let Postfix know about the IPs that it should consider part of the LAN:
We'll assume
192.168.1.0/24
is your local LAN. You can safely skip this step if you don't have other machines in the same local network.sudo postconf -e "mynetworks = 127.0.0.0/8, 192.168.1.0/24"
-
Configure Postfix to receive mail on all interfaces, which includes the internet:
sudo postconf -e "inet_interfaces = all"
-
Configure Postfix to use the
+
delimiter for sub-addressing:sudo postconf -e "recipient_delimiter = +"
-
Restart Postfix:
sudo service postfix restart
-
Test SMTP under the new setup:
-
Connect to the SMTP server:
telnet gitlab.example.com 25
You should see a prompt like this:
Trying 123.123.123.123... Connected to gitlab.example.com. Escape character is '^]'. 220 gitlab.example.com ESMTP Postfix (Ubuntu)
If you get a
Connection refused
error instead, make sure your firewall is setup to allow inbound traffic on port 25. -
Send the
incoming
user a dummy email to test SMTP, by entering the following into the SMTP prompt:ehlo gitlab.example.com mail from: [email protected] rcpt to: [email protected] data Subject: Re: Some issue Sounds good! . quit
(Note: The
.
is a literal period on its own line) -
Check if the
incoming
user received the email:su - incoming MAIL=/home/incoming/Maildir mail
You should see output like this:
"/home/incoming/Maildir": 1 message 1 unread >U 1 [email protected] 59/2842 Re: Some issue
Quit the mail app:
q
-
Log out of the
incoming
account and go back to beingroot
:logout
-
-
Test IMAP under the new setup:
-
Connect to the IMAP server:
telnet gitlab.example.com 143
You should see a prompt like this:
Trying 123.123.123.123... Connected to mail.example.gitlab.com. Escape character is '^]'. - OK [CAPABILITY IMAP4rev1 UIDPLUS CHILDREN NAMESPACE THREAD=ORDEREDSUBJECT THREAD=REFERENCES SORT QUOTA IDLE ACL ACL2=UNION] Courier-IMAP ready. Copyright 1998-2011 Double Precision, Inc. See COPYING for distribution information.
-
Sign in as the
incoming
user to test IMAP, by entering the following into the IMAP prompt:a login incoming PASSWORD
Replace PASSWORD with the password you set on the
incoming
user earlier.You should see output like this:
a OK LOGIN Ok.
-
Disconnect from the IMAP server:
a logout
-
If all the tests were successful, Postfix is all set up and ready to receive email! Continue with the Reply by email guide to configure GitLab.
This document was adapted from https://help.ubuntu.com/community/PostfixBasicSetupHowto, by contributors to the Ubuntu documentation wiki.