Mailcow

Install a complete self-hosted mail server with Mailcow Dockerized, SMTP, IMAP, webmail, anti-spam and DKIM included

Mailcow Dockerized is a complete mail server stack running entirely on Docker. It includes Postfix (SMTP), Dovecot (IMAP), SOGo (webmail), Rspamd (anti-spam), ClamAV (antivirus), automatic TLS and a web admin panel.

Prerequisites

Minimum 2 vCPU, 4 GB RAM (6 GB recommended with ClamAV)
A dedicated domain or subdomain, e.g. mail.yourdomain.com
Ports 25, 80, 110, 143, 443, 465, 587, 993, 995 open on the firewall
Reverse DNS (PTR) set to mail.yourdomain.com: essential for email deliverability
Docker and Docker Compose installed

Many VPS providers block port 25 by default to prevent spam. Check with DeluxHost support if your VPS has outbound port 25 open before proceeding.

DNS Configuration

Before installing, configure these DNS records for your domain:

Type	Name	Value
A	`mail`	`YOUR_SERVER_IP`
MX	`@`	`mail.yourdomain.com` (priority 10)
TXT	`@`	`v=spf1 mx ~all`
CNAME	`autodiscover`	`mail.yourdomain.com`
CNAME	`autoconfig`	`mail.yourdomain.com`

DKIM and DMARC records will be configured after installation.

Installation

Clone the repository

cd /opt
git clone https://github.com/mailcow/mailcow-dockerized
cd mailcow-dockerized

Generate configuration

./generate_config.sh

The script will ask:

Mail server hostname (FQDN): mail.yourdomain.com
Timezone: e.g. Europe/Rome

This generates the mailcow.conf file.

Start Mailcow

docker compose pull
docker compose up -d

The first startup takes several minutes. Monitor with:

docker compose logs -f

First Access

Open https://mail.yourdomain.com in your browser.

Default credentials:

Username: admin
Password: moohoo

Change the admin password immediately from Configuration → Access → Admin password.

Creating a Mailbox

Go to Mail Setup → Domains → Add domain
Add yourdomain.com and click Save
Go to Mailboxes → Add mailbox
Fill in username, full name and password
Click Add

DKIM Configuration

DKIM digitally signs outgoing emails, essential for deliverability.

Go to Configuration → ARC/DKIM keys
Select your domain
Click Generate (or use key length 2048)
Copy the DKIM TXT record shown
Add it to your DNS as a TXT record on dkim._domainkey.yourdomain.com

DMARC record (recommended)

Add a TXT record on _dmarc.yourdomain.com:

v=DMARC1; p=quarantine; rua=mailto:dmarc@yourdomain.com; ruf=mailto:dmarc@yourdomain.com; fo=1

Start with p=none to monitor without rejecting emails, then switch to p=quarantine or p=reject once everything is working.

Email Client Configuration

IMAP (incoming mail)

Server: mail.yourdomain.com
Port: 993 (SSL/TLS)

SMTP (outgoing mail)

Server: mail.yourdomain.com
Port: 587 (STARTTLS) or 465 (SSL/TLS)

Webmail (SOGo)

URL: https://mail.yourdomain.com/SOGo

Maintenance and Updates

Update Mailcow

cd /opt/mailcow-dockerized

# Pull update script
./update.sh

The script handles stopping containers, pulling new images and restarting.

Backup

# Backup all data
cd /opt/mailcow-dockerized
./helper-scripts/backup_and_restore.sh backup all

Backups are saved to /var/mailcow_backups/ by default.

Restore

./helper-scripts/backup_and_restore.sh restore

Useful Commands

# Check all container status
cd /opt/mailcow-dockerized
docker compose ps

# View logs for a specific service
docker compose logs -f postfix-mailcow
docker compose logs -f rspamd-mailcow
docker compose logs -f dovecot-mailcow

# Restart a single service
docker compose restart postfix-mailcow

# Restart all Mailcow
docker compose restart

Rspamd (Anti-spam)

Rspamd is the anti-spam engine. Access its web interface at:

https://mail.yourdomain.com/rspamd

The password is in mailcow.conf:

grep RSPAMD_PASSWORD /opt/mailcow-dockerized/mailcow.conf

From the Rspamd interface you can view scores of analyzed emails, whitelist/blacklist senders and adjust spam thresholds.

Deliverability Check

After configuration, verify your mail server with:

mail-tester.com, sends an email to check SPF, DKIM, DMARC
mxtoolbox.com, verifies MX, blacklists, PTR

A score of 10/10 on mail-tester is achievable with Mailcow if SPF, DKIM, DMARC and reverse DNS are configured correctly. This is essential to avoid emails landing in spam with Gmail, Outlook and other providers.

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