Mailu

Mailu is a simple yet full-featured email server distributed as a set of Docker images. It provides the core protocols needed to run your own mail infrastructure, plus webmail and an administration interface.

Key Features

• SMTP, Submission, IMAP/IMAP+, and optional POP3 support
• Multiple webmail options and a built-in administration UI
• Aliases, domain aliases, custom routing, auto-forward and auto-reply
• Fetched accounts (fetchmail-style) and ManageSieve support
• Per-domain delegation, global admins, announcements, and mailbox quotas
• Security features including enforced TLS, Let’s Encrypt integration, outgoing DKIM, DMARC/SPF, and anti-spoofing options
• Anti-spam features such as greylisting and auto-learning, plus optional antivirus scanning

Use Cases

• Hosting email for personal domains or small organizations with a web-based admin panel
• Running multi-domain mail hosting with delegated per-domain administration
• Deploying a containerized mail stack with DKIM/DMARC/SPF and spam filtering

Limitations and Considerations

• Deliverability depends on correct DNS configuration (SPF, DKIM, DMARC, rDNS) and IP reputation
• Operating a mail server requires ongoing maintenance (TLS, spam rules, storage quotas, and monitoring)

Mailu focuses on providing a complete, containerized mail stack using standard components rather than a full groupware suite. It is designed to be straightforward to deploy and maintain while offering the security and administrative features expected from a modern mail server.