Setup for Postfix + Dovecot on Ubuntu Server 24.04 LTS

by | Nov 5, 2025 | Uncategorized

Here’s a minimal and reliable setup for Postfix + Dovecot on Ubuntu Server 24.04 LTS (Noble Numbat).
This covers local delivery, IMAP/SMTP auth, and TLS.

1. Install packages

sudo apt update
sudo apt install postfix dovecot-imapd dovecot-pop3d dovecot-lmtpd

During setup, choose:

  • General type of mail configuration: Internet Site

  • System mail name: your domain (e.g. example.com)

2. Configure Postfix

Edit /etc/postfix/main.cf:

sudo nano /etc/postfix/main.cf

Ensure these key lines exist or modify accordingly:

myhostname = mail.example.com
myorigin = /etc/mailname
mydestination = localhost
relayhost =
inet_interfaces = all
inet_protocols = ipv4

home_mailbox = Maildir/
mailbox_command =
smtpd_banner = $myhostname ESMTP

# TLS
smtpd_tls_cert_file=/etc/letsencrypt/live/example.com/fullchain.pem
smtpd_tls_key_file=/etc/letsencrypt/live/example.com/privkey.pem
smtpd_use_tls=yes
smtpd_tls_auth_only = yes
smtpd_tls_security_level = may

# Authentication via Dovecot
smtpd_sasl_type = dovecot
smtpd_sasl_path = private/auth
smtpd_sasl_auth_enable = yes
smtpd_recipient_restrictions =
    permit_sasl_authenticated,
    permit_mynetworks,
    reject_unauth_destination

Reload:

sudo systemctl restart postfix
sudo systemctl enable postfix

3. Configure Dovecot

Edit /etc/dovecot/dovecot.conf:

protocols = imap pop3 lmtp

Edit /etc/dovecot/conf.d/10-mail.conf:

mail_location = maildir:~/Maildir

Edit /etc/dovecot/conf.d/10-auth.conf:

disable_plaintext_auth = yes
auth_mechanisms = plain login
!include auth-system.conf.ext

Edit /etc/dovecot/conf.d/10-master.conf:
Uncomment and modify the unix_listener for Postfix:

service auth {
  unix_listener /var/spool/postfix/private/auth {
    mode = 0660
    user = postfix
    group = postfix
  }
}

Edit /etc/dovecot/conf.d/10-ssl.conf:

ssl = required
ssl_cert = </etc/letsencrypt/live/example.com/fullchain.pem
ssl_key = </etc/letsencrypt/live/example.com/privkey.pem

Restart:

sudo systemctl restart dovecot
sudo systemctl enable dovecot

4. Create a Mail User

sudo adduser mailuser
sudo mkdir -p /home/mailuser/Maildir
sudo chown -R mailuser:mailuser /home/mailuser/Maildir

5. Test

  • IMAP: openssl s_client -connect mail.example.com:993 -crlf

  • SMTP Auth: telnet mail.example.com 587

  • Or use a mail client with IMAP (993 SSL/TLS) and SMTP (587 STARTTLS).

6. (Optional) TLS via Let’s Encrypt

If not already done:

sudo apt install certbot
sudo certbot certonly --standalone -d mail.example.com

Set auto-renew:

sudo crontab -e

Add:

0 3 * * * certbot renew --quiet && systemctl reload postfix dovecot

Would you like the configuration extended to handle virtual domains/users via MySQL or just system accounts only?