Email Tutorials - Herong's Tutorial Examples - v1.03, by Herong Yang
Install and Configure Dovecot on CentOS
This section provides a tutorial example on how to install, configure and run Dovecot server on CentOS systems.
Installing Dovecot on CentOS 8 is relatively easy, since it has a ready-to-run binary package in CentOS repository. Here is what I did to install, configure and run Dovecot on my CentOS 8 computer.
1. Install Dovecot with "dnf" command.
herong$ sudo dnf install dovecot
...
Installed:
dovecot-1:2.3.8-2.el8_2.2.x86_64
clucene-core-2.3.3.4-31.20130812.e8e3d20git.el8.x86_64
2. Configure Dovecot. The "mail_location = maildir:~/Maildir" needs to match how Postfix manages mail boxes on the server.
herong$ cd /etc/dovecot/
herong$ sudo cp dovecot.conf dovecot-bck.conf
herong$ sudo vi /etc/dovecot/dovecot.conf
protocols = imap pop3 lmtp submission
herong$ sudo vi /etc/dovecot/conf.d/10-mail.conf
mail_location = maildir:~/Maildir
herong$ sudo vi /etc/dovecot/conf.d/10-auth.conf
disable_plaintext_auth = yes
auth_mechanisms = plain login
herong$ sudo vi /etc/dovecot/conf.d/10-master.conf
...
service auth {
unix_listener auth-userdb {
#mode = 0666
user = postfix
group = postfix
}
...
}
3. Make sure that Postfix is running.
herong$ ps -ef | grep postfix postfix 14318 31224 0 20:44 ? 00:00:00 pickup -l -t unix -u root 31224 1 0 Nov13 ? 00:00:01 /usr/libexec/postfix/master -w postfix 31226 31224 0 Nov13 ? 00:00:00 qmgr -l -t unix -u postfix 31302 31224 0 Nov13 ? 00:00:00 tlsmgr -l -t unix -u
4. Enable Dovecot and start it. Too bad, it failed to bind on port 587.
herong$ sudo systemctl enable dovecot Created symlink /etc/systemd/system/multi-user.target.wants/dovecot.service -> /usr/lib/systemd/system/dovecot.service. herong$ sudo systemctl start dovecot herong$ sudo systemctl status dovecot 06:39:23 localhost.localdomain dovecot[30210]: Error: bind(::, 587) failed: Permission denied
5. Check to see who is listening on port 587. I see Postfix master program in the output. So both Postfix and Dovecot can listen to port 587? I will check it out later.
herong$ sudo netstat -lpt Proto Local Address Foreign Address State PID/Program name tcp 0.0.0.0:25 0.0.0.0:* LISTEN 31224/master tcp 0.0.0.0:587 0.0.0.0:* LISTEN 31224/master ... herong$ ps -ef | grep master root 31224 1 0 Nov13 ? /usr/libexec/postfix/master -w
6. Turn off port 587 on Dovecot by setting the port number to 0 with "port=0" on the "submission" service.
herong$ sudo vi /etc/dovecot/conf.d/10-master.conf
...
service submission-login {
inet_listener submission {
#port = 587
#port = 0 # bad syntax. do not leave any space before and after the =
port=0
}
}
7. Start Dovecot again.
herong$ sudo systemctl start dovecot
herong$ sudo systemctl status dovecot
* dovecot.service - Dovecot IMAP/POP3 email server
Loaded: loaded (/usr/lib/systemd/system/dovecot.service; enabled; vendor preset: disabled)
Active: active (running) since 2023-11-15 08:00:09 EST; 14s ago
Docs: man:dovecot(1)
http://wiki2.dovecot.org/
Process: 31486 ExecStop=/usr/bin/doveadm stop (code=exited, status=0/SUCCESS)
Process: 31495 ExecStartPre=/usr/libexec/dovecot/prestartscript (code=exited, status=0/)
Main PID: 31503 (dovecot)
Tasks: 4 (limit: 26213)
Memory: 5.6M
CGroup: /system.slice/dovecot.service
|-31503 /usr/sbin/dovecot -F
|-31504 dovecot/anvil
|-31505 dovecot/log
|-31506 dovecot/config
systemd[1]: Starting Dovecot IMAP/POP3 email server...
systemd[1]: Started Dovecot IMAP/POP3 email server.
dovecot[31503]: master: Dovecot v2.3.8 (9df20d2db) starting up for imap, pop3, lmtp, submission
Cool! I think my Dovecot server is running and ready to handle IMAP and POP3 requests.
Table of Contents
Postfix - Mail Transport Agent (MTA)
SSL/TLS Secure Connections with Postfix Server
►Dovecot - IMAP and POP3 Server
►Install and Configure Dovecot on CentOS
Test Dovecot IMAP Server with "telnet" Client
Test Dovecot POP3 Server with "telnet" Client
Keep Deleted Emails on Dovecot
Turn on Dovecot Server Logging for Troubleshooting
"doveadm" Command - Dovecot's Administration Utility
SSL/TLS Secure Connections with Dovecot Server
Email Client Tools - Mail User Agents (MUA)