How to Install Mailcow Mail Server via Docker

Mailcow is a complete open-source mail server solution that provides SMTP, IMAP, spam filtering, antivirus protection and a modern web interface. Mailcow uses Docker containers to simplify installation and management.

Minimum Server Requirements

• Ubuntu 22.04 server
• Minimum 6 GB RAM
• 2 CPU cores
• 40 GB disk space
• Dedicated public IP address
• Full DNS control over your domain

Recommended Domain Structure

mail.example.com → Mailcow server
example.com → main website

Step 1 – Connect to Your Server

ssh root@SERVER_IP

Step 2 – Update Your System

apt update && apt upgrade -y

Step 3 – Install Docker

curl -fsSL https://get.docker.com | sh

apt install docker-compose-plugin -y

Step 4 – Clone Mailcow Repository

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

Step 5 – Generate Configuration

./generate_config.sh

Enter your mail hostname:

mail.example.com

Step 6 – Configure Firewall

ufw allow 25
ufw allow 465
ufw allow 587
ufw allow 143
ufw allow 993
ufw allow 110
ufw allow 995
ufw allow 80
ufw allow 443

Step 7 – Configure DNS Records

A Record

mail.example.com → SERVER_IP

MX Record

example.com → mail.example.com (priority 10)

SPF Record

v=spf1 mx ip4:SERVER_IP ~all

DMARC Record

_dmarc.example.com TXT
v=DMARC1; p=none; rua=mailto:[email protected]

Reverse DNS

Your server IP should resolve to:

mail.example.com

Step 8 – Start Mailcow

docker compose pull
docker compose up -d

Step 9 – Access the Mailcow Interface

https://mail.example.com

Default login:

Username: admin
Password: moohoo

Step 10 – Add Your Domain

Go to:

Configuration → Mail Setup

Add your domain and create mailboxes.

Step 11 – Configure DKIM

Go to:

Configuration → DKIM Keys

Generate DKIM keys and add the DNS record provided.

Email Client Settings

IMAP Server: mail.example.com
Port: 993
Encryption: SSL/TLS

SMTP Server: mail.example.com
Port: 587
Encryption: STARTTLS

Update Mailcow

cd mailcow-dockerized
./update.sh

Security Recommendations

• Always configure SPF, DKIM and DMARC
• Use strong passwords
• Enable firewall protection
• Keep Mailcow updated

Conclusion

Mailcow provides a powerful self-hosted email solution with spam filtering, antivirus protection and modern webmail.