What features does Mailu provide as a mail server?

Updated

Mailu is a full-featured mail server delivered as a set of Docker images, and it is free software — free both as in cost and as in freedom. It is designed to be easy to set up and maintain without shipping proprietary software or unrelated groupware features. If you want a self-hosted mail server that covers standard mail protocols, webmail, administration, security, and antispam in one stack, Mailu is built for that purpose. The feature list below reflects what the project documents on its own site.

Standard email server

Mailu provides the core protocols you expect from a mail server:

  • IMAP and IMAP+ for mailbox access
  • SMTP and Submission for sending and relaying mail
  • Auto-configuration profiles for clients, so mail clients can be set up with less manual entry

This means Mailu can serve as the primary mail server for a domain, handling both incoming and outgoing mail alongside mailbox retrieval.

Advanced email features

Beyond basic delivery, Mailu documents several features that matter for real-world mail management:

  • Aliases — route mail to alternate addresses
  • Domain aliases — serve multiple domain names from one setup
  • Custom routing — control how messages are directed
  • Full-text search of email attachments — search inside attached files, not just message bodies

Web access

Mailu includes a browser-based side to the server:

  • Multiple Webmails — more than one webmail option is available
  • Administration interface — manage the server through the web

User features

For individual accounts, Mailu documents:

  • Aliases
  • Auto-reply
  • Auto-forward
  • Fetched accounts (pulling mail from external accounts)
  • ManageSieve (for server-side mail filtering rules)

Admin features

Administrators get tools for running the server across one or many domains:

  • Global admins
  • Announcements
  • Per-domain delegation
  • Quotas

Security

Mailu documents a security-focused feature set:

  • Enforced TLS
  • DANE
  • MTA-STS
  • Let's Encrypt integration
  • Outgoing DKIM
  • Anti-virus scanner
  • Snuffleupagus
  • Blocking of malicious attachments

Antispam

Spam handling in Mailu includes:

  • Auto-learn
  • Greylisting
  • DMARC and SPF
  • Anti-spoofing

Freedom and openness

Mailu is built entirely from FOSS components and includes no tracker. The project is open to suggestions and external contributions. Its documentation is written as part of the repository and evolves with it, so you should consult the documentation version that matches the Mailu version you are running.

How to decide whether Mailu fits your needs

Use the list above as a checklist against your requirements:

If you need… Mailu documents…
Standard mail protocols IMAP, IMAP+, SMTP, Submission
Easy client setup Auto-configuration profiles
Multiple domains Domain aliases, per-domain delegation
Web-based management Admin interface, multiple Webmails
Server-side filtering ManageSieve, auto-reply, auto-forward
Strong transport security Enforced TLS, DANE, MTA-STS, Let's Encrypt, DKIM
Spam and malware protection Antispam (auto-learn, greylisting, DMARC, SPF), anti-virus, malicious attachment blocking
No proprietary components All FOSS components, no tracker

If your requirements map cleanly onto these documented features, Mailu is a candidate worth evaluating. If you need functionality outside this list — such as groupware or proprietary integrations — note that Mailu explicitly does not ship unrelated features often found in popular groupware, so those would need to come from elsewhere.