Mailu

v2024.06

Full-featured open-source mail server as a set of Docker containers: SMTP (Postfix), IMAP (Dovecot), Rspamd antispam, admin UI with DKIM management and Roundcube webmail.

email mail-server smtp imap antispam webmail

Deploy on Notploy

Website GitHub Documentation

How to deploy

Deploy Mailu on Notploy

Install Notploy on your server if you haven't already.
In your Notploy panel, open a project and click Create Service → Template.
Search for Mailu and click Create — Notploy configures domains, environment variables, and volumes for you.

Alternatively, create a Compose service, go to Advanced → Import from Base64, and paste this payload:

base64

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

Reference files

Configuration

The exact Docker Compose and template configuration this template deploys.

Usage guide

Instructions

Mailu

Getting started

Point the domain you assign in Dokploy (for example mail.example.com) at your server before deploying: an A record, plus an MX record for your mail domain targeting it.
Deploy the template and open the domain: /webmail is Roundcube, /admin is the admin UI.
Log in at /admin with admin@<your domain> and the auto-generated INITIAL_ADMIN_PW (Dokploy → your service → Environment). The account is created only on first boot (INITIAL_ADMIN_MODE=ifmissing); change the password from the admin UI afterwards.
In the admin UI, open Mail domains → your domain → Details and create the DNS records it shows (SPF, DKIM, DMARC). Also set the PTR/reverse DNS record of your server IP to your mail hostname — most providers require this to accept your mail.

Ports

The mail protocol ports are published directly on the host: 25 (SMTP), 465 (SMTPS), 587 (submission) and 993 (IMAPS). The deployment fails to start if another mail server (or a previous Mailu deployment) already binds them on the same machine. Many VPS providers block outbound port 25 by default — ask your provider to unblock it, or configure a relay host in Mailu.

TLS

The web UI is served through Traefik like any other Dokploy app. Enable HTTPS with Let's Encrypt on the Dokploy domain: the web login cookie requires HTTPS, and Mailu's internal certbot self-check follows Traefik's HTTP→HTTPS redirect and needs a valid certificate there.
The mail ports get their own Let's Encrypt certificate: the front container runs certbot internally and answers the HTTP-01 challenge through Traefik on port 80. This only succeeds once the DNS record of your domain points at the server. If the certificate was obtained after the first boot, restart the front service once so the TLS mail listeners (465/587/993) come up.

Notes

SUBNET (default 172.16.0.0/12) is the network range Mailu trusts for its internal traffic (Postfix relay/XCLIENT, Dovecot proxying, Rspamd). It covers Docker's default address pools; if your Docker daemon uses custom pools, adjust it to match. Note this means other containers on the same Docker host are treated as trusted senders.
The containers use public DNSSEC-validating resolvers (1.1.1.1, 8.8.8.8) as upstream DNS: the admin container requires DNSSEC validation and Postfix uses it for DANE. Heavy production use benefits from a dedicated local resolver instead, because public resolvers are rate-limited by DNSBLs (see the Mailu DNS FAQ).
Additional mail domains, users, aliases and fetchmail can be managed in the admin UI. ClamAV antivirus is not included in this template to keep memory usage low (it needs >1 GB RAM); see the Mailu docs to add it.

Poste.io

Version latest

Complete mail server solution with SMTP, IMAP, POP3, antispam, antivirus, web administration and webmail client.

emailmail-serversmtp

Stalwart

Version latest

Stalwart Mail Server is an open-source mail server solution with JMAP, IMAP4, POP3, and SMTP support and a wide range of modern features. It is written in Rust and designed to be secure, fast, robust and scalable.

emailsmtpjmap

MailCatcher NG

Version 1.6.8

MailCatcher NG runs a super simple SMTP server which catches any message sent to it to display in a web interface. Point your app's SMTP settings at mailcatcher-ng:1025 and inspect every captured email in the browser.

emailsmtpdevelopment