# Mailu — Docker-Based Self-Hosted Mail Server

> Mailu is a full-featured, Docker-based mail server suite that bundles SMTP, IMAP, webmail, antispam, antivirus, and an admin UI into a set of coordinated containers for easy deployment and management.

## Install

Save as a script file and run:

# Mailu — Docker-Based Self-Hosted Mail Server

## Quick Use
```bash
# Generate docker-compose.yml via the online setup wizard
# https://setup.mailu.io
docker compose -p mailu up -d
# Admin panel: https://mail.yourdomain.com/admin
```

## Introduction
Mailu packages every component of a production mail server into Docker containers that work together out of the box. Rather than manually configuring Postfix, Dovecot, and a dozen related services, Mailu provides an opinionated, container-native stack with a web-based setup wizard and admin panel. It targets small to medium deployments where simplicity and security matter more than extreme customization.

## What Mailu Does
- Runs Postfix (SMTP) and Dovecot (IMAP/POP3) in isolated containers with automatic TLS via Let's Encrypt
- Includes Rspamd for spam filtering with Bayesian learning and optional ClamAV for virus scanning
- Provides Roundcube or Rainloop as webmail clients accessible from the browser
- Offers a web admin panel for managing domains, users, aliases, and relays
- Handles DKIM signing, SPF, DMARC, and autoconfig/autodiscover for email clients

## Architecture Overview
Mailu uses Docker Compose to orchestrate a set of microservice containers. The front container (Nginx) handles TLS termination, HTTP routing, and SMTP/IMAP proxying. Behind it, dedicated containers run Postfix, Dovecot, Rspamd, an optional antivirus (ClamAV), the admin interface (Flask-based), and the chosen webmail. A Redis instance coordinates rate limiting and Rspamd state. All persistent data lives in Docker volumes, making backups straightforward.

## Self-Hosting & Configuration
- Use the online setup wizard at setup.mailu.io to generate a docker-compose.yml tailored to your domain
- Requires a server with at least 2 GB RAM (4 GB if enabling ClamAV) and ports 25, 143, 443 open
- Configure DNS records (MX, SPF, DKIM, DMARC) as shown in the admin panel's DNS status page
- Environment variables in mailu.env control all settings: domain, TLS mode, message size limits, and features
- Update by pulling new images and running docker compose up -d; data volumes are preserved

## Key Features
- Container-native architecture with each service isolated in its own Docker container
- Web-based setup wizard that generates a ready-to-run Compose file for your configuration
- Rspamd integration with auto-learning, greylisting, and DKIM/ARC signing
- Multi-domain support with per-domain quotas, aliases, and catch-all addresses
- Fetchmail integration to pull messages from external accounts into local mailboxes

## Comparison with Similar Tools
- **Mail-in-a-Box** — Single-server Bash installer; simpler but less modular than Mailu's container approach
- **Mailcow** — Docker-based like Mailu but uses SOGo for groupware; heavier resource footprint
- **iRedMail** — Script-based installer for bare-metal; more flexible OS support but no container isolation
- **Docker Mailserver** — Minimal single-container mail setup; lighter but lacks Mailu's admin UI and wizard

## FAQ
**Q: How much RAM does Mailu need?**
A: A basic setup runs on 2 GB. Enabling ClamAV antivirus adds roughly 1-2 GB of memory usage.

**Q: Can I use Mailu with an existing reverse proxy?**
A: Yes. Mailu supports running behind Traefik, Nginx, or Caddy by configuring the TLS_FLAVOR and proxy settings in mailu.env.

**Q: Does Mailu support two-factor authentication?**
A: The admin panel supports 2FA for admin accounts. Webmail 2FA depends on the chosen webmail client.

**Q: How do I migrate from another mail server?**
A: Use imapsync or the Fetchmail feature to pull existing messages from your old IMAP server into Mailu mailboxes.

## Sources
- https://github.com/Mailu/Mailu
- https://mailu.io/master/

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Source: https://tokrepo.com/en/workflows/e1a3cd28-401c-11f1-9bc6-00163e2b0d79
Author: Script Depot