Mailu

What is Mailu?

Mailu is a full self-hosted mail server suite: SMTP, IMAP, webmail, antispam, and antivirus, all in one stack. Unlike the other mail services in Laradock (Mailpit, MailHog, MailDev, MailCatcher), which only catch and display outgoing dev email, Mailu is a real mail server capable of sending and receiving actual mail for a domain you control. Laradock wires up the whole Mailu stack as a group of containers.

Start Mailu

docker compose up -d mailu

mailu/compose.yml defines mailu as the umbrella service, depending on mailu-front (nginx), mailu-imap (Dovecot), mailu-smtp (Postfix), mailu-antispam (rspamd), mailu-antivirus (ClamAV), mailu-webdav, mailu-admin, and mailu-webmail (Rainloop by default), plus mailu-fetchmail. Starting mailu brings up the whole chain automatically. mailu-admin also depends on redis.

Stop Mailu

docker compose stop mailu mailu-front mailu-imap mailu-smtp mailu-antispam mailu-antivirus mailu-webdav mailu-admin mailu-webmail mailu-fetchmail

docker compose stop mailu alone only stops the umbrella container; the underlying mail services keep running since compose doesn't cascade stop down depends_on. Data (mail, DKIM keys, certs, webmail state) lives under DATA_PATH_HOST/mailu/.

Configuration

All settings live in mailu/defaults.env and can be overridden by adding the same line to your own .env. This is a large suite, so only the most commonly touched settings are listed here, the file has more (DMARC report addresses, welcome-email text, statistics opt-out, password hashing scheme).

Variable	Default	What it does
MAILU_VERSION	latest	Image tag shared by every Mailu container.
MAILU_DOMAIN	example.com	Main mail domain.
MAILU_HOSTNAMES	mail.example.com,alternative.example.com,yetanother.example.com	Comma-separated hostnames this server answers to.
MAILU_POSTMASTER	admin	Local part of the postmaster address (postmaster@+MAILU_DOMAIN).
MAILU_HTTP_PORT	6080	Host-side port for the web admin/webmail (container port 80).
MAILU_HTTPS_PORT	60443	Host-side port for HTTPS (container port 443).
MAILU_INIT_ADMIN_USERNAME	laradock	Username for the admin account created on first boot.
MAILU_INIT_ADMIN_PASSWORD	laradock	Password for that admin account.
MAILU_SECRET_KEY	ChangeMeChangeMe	Random 16-byte secret used internally; change this before any real use.
MAILU_TLS_FLAVOR	cert	TLS mode: letsencrypt, cert, notls, or mail.
MAILU_MESSAGE_SIZE_LIMIT	50000000	Max accepted message size in bytes (default 50MB).
MAILU_RELAYHOST	(empty)	Upstream SMTP relay for outgoing mail, if any.
MAILU_RELAYNETS	172.16.0.0/12	Networks granted relay permission; must include your Docker network.
MAILU_RECIPIENT_DELIMITER	+	Character separating the local part from a custom tag (user+tag@domain).
MAILU_WEBMAIL	rainloop	Which webmail client to run (rainloop, roundcube, or none).
MAILU_WEBDAV	radicale	DAV server implementation (radicale or none).
MAILU_ADMIN	true	Whether the admin web interface is exposed.
MAILU_AUTH_RATELIMIT	10/minute;1000/hour	Login rate limit per source IP.
MAILU_RECAPTCHA_PUBLIC_KEY	(placeholder)	reCAPTCHA public key, required for the signup form.
MAILU_RECAPTCHA_PRIVATE_KEY	(placeholder)	reCAPTCHA private key, required for the signup form.

Set up a domain

You'll need a registered domain and a reCAPTCHA key pair for the signup email flow. In your .env:

MAILU_RECAPTCHA_PUBLIC_KEY=<YOUR_RECAPTCHA_PUBLIC_KEY>
MAILU_RECAPTCHA_PRIVATE_KEY=<YOUR_RECAPTCHA_PRIVATE_KEY>
MAILU_DOMAIN=laradock.io
MAILU_HOSTNAMES=mail.laradock.io

Then start the stack and open http://YOUR_DOMAIN (or https:// with a proper MAILU_TLS_FLAVOR).

Ports and real mail protocols

Unlike the other mail services, Mailu's mailu-front container publishes real mail protocol ports directly, hardcoded in mailu/compose.yml rather than driven by env vars: 110 (POP3), 143 (IMAP), 993 (IMAPS), 995 (POP3S), 25 (SMTP), 465 (SMTPS), 587 (submission). Only the web ports (MAILU_HTTP_PORT, MAILU_HTTPS_PORT) are configurable via .env.

Common issues

• Signup form doesn't work. You still have placeholder reCAPTCHA keys (MAILU_RECAPTCHA_PUBLIC_KEY/MAILU_RECAPTCHA_PRIVATE_KEY). Generate a real pair and rebuild.
• Mail rejected or not relayed. Check MAILU_RELAYNETS includes your Docker network range, and that MAILU_RELAYHOST is set correctly if you're relaying through an upstream SMTP provider.
• Only the mailu container is running, the rest aren't. depends_on only affects up, not stop. If you tore down the stack partially, bring everything back with docker compose up -d mailu.
• Data lost between restarts on multi-project setups. Two Laradock projects on the same machine need unique COMPOSE_PROJECT_NAME and DATA_PATH_HOST values, otherwise they share the same DATA_PATH_HOST/mailu/ data on disk.
• Just testing outgoing mail in dev, not building a real mail server? Mailu is overkill for that, use a lightweight catcher instead.

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Just need to catch dev email, not run a real mail server? See Mailpit. New to Laradock? Start with Getting Started.