Comprehensive Guide to Installing iRedMail on Linux

1. What is Dovecot?

Dovecot is a high‑performance, secure Mail Delivery Agent (MDA) and Mail Access Server. Its primary responsibilities include:

• Providing IMAP and POP3 access to users
• Authenticating email users (SASL)
• Delivering messages to mailboxes (LDA/LMTP)

In iRedMail, Dovecot is essential because:

• It delivers emails to user mailboxes
• It acts as the authentication backend for Postfix (SMTP Auth)

2. Dovecot’s Role in iRedMail Architecture

Incoming Mail Flow

Internet
   ↓
Postfix (SMTP)
   ↓
Amavis (Scan)
   ↓
Dovecot (LDA / LMTP)
   ↓
Mailbox (Maildir)

Outgoing Mail Flow

Mail Client → SMTP Auth → Postfix
                     ↑
                  Dovecot (Auth)

3. Dovecot Service Architecture

Dovecot is a daemon‑based service composed of multiple processes:

• dovecot
• auth
• imap
• pop3
• lmtp

Service control:

systemctl status dovecot

4. Dovecot Installation in iRedMail

Dovecot is installed and configured automatically by iRedMail. To verify installation:

rpm -qa | grep dovecot        # Rocky / Alma
apt list --installed | grep dovecot   # Ubuntu

5. Important Dovecot Paths

Path	Description
/etc/dovecot/	Main configuration directory
/etc/dovecot/dovecot.conf	Primary configuration file
/etc/dovecot/conf.d/	Modular configuration files
/var/vmail/	User mailboxes
/var/log/maillog	Logs

6. Key Dovecot Configuration

6.1 Protocols

protocols = imap pop3 lmtp

6.2 Mailbox Format

mail_location = maildir:/var/vmail/%d/%n/Maildir

Maildir advantages:

• Better performance
• Easy backup

6.3 User / Group

mail_uid = 2000
mail_gid = 2000

This corresponds to the vmail user/group created by iRedMail.

6.4 Authentication Backend

Dovecot in iRedMail can authenticate users via MariaDB/MySQL or LDAP.

Example SQL Authentication:

passdb {
  driver = sql
  args = /etc/dovecot/dovecot-sql.conf
}

userdb {
  driver = sql
  args = /etc/dovecot/dovecot-sql.conf
}