Modoboa is a Python/Django-based email server management platform that wraps Postfix and Dovecot with a modern web interface. Install via their automated installer on Ubuntu or Debian, configure DNS records, and you get multi-domain email hosting with web admin, webmail, calendar, anti-spam (Rspamd or SpamAssassin), and auto-reply. It's lighter than Mailcow (runs on 1GB RAM) and more polished than raw iRedMail, but has a smaller community.
Modoboa Setup Guide: Modern Email Server with Web Admin
Modoboa: The Lightweight Contender
Modoboa is the self-hosted email platform that doesn't get enough attention. It offers a clean web interface, multi-domain management, and a complete email stack — all running on hardware that's too small for Mailcow.
If you need a mail server for a few domains on a budget VPS and want something more polished than raw Postfix/Dovecot, Modoboa fits the gap. See our comparison guide for how it stacks up.
Prerequisites
- Fresh Ubuntu 22.04 or Debian 12 — clean install, no other services
- 1 GB RAM minimum (2 GB with ClamAV)
- Clean IP address — check MXToolbox blacklists
- Domain name with DNS access
- Port 25 open on your VPS provider
- PTR record configured in VPS control panel
Installation
Modoboa provides an automated installer:
git clone https://github.com/modoboa/modoboa-installer.git
cd modoboa-installer
sudo python3 run.py --stop-after-configfile-check yourdomain.com
This generates a configuration file at installer.cfg. Review and edit it:
[general]
hostname = mail.yourdomain.com
[certificate]
type = letsencrypt
[modoboa]
# Keep defaults unless you have specific requirements
[automx]
enabled = true
[rspamd]
enabled = true
[clamav]
enabled = false # Enable if you have 2GB+ RAM
Then run the full installation:
sudo python3 run.py yourdomain.com
The installer handles Postfix, Dovecot, Nginx, Rspamd, Let's Encrypt, and Modoboa itself. Takes 10-15 minutes.
DNS Configuration
# MX Record
yourdomain.com MX 10 mail.yourdomain.com
# A Record
mail.yourdomain.com A [your-server-ip]
# SPF
yourdomain.com TXT "v=spf1 ip4:[your-server-ip] -all"
# DKIM (generate in Modoboa admin → Domains → DKIM)
dkim._domainkey.yourdomain.com TXT "v=DKIM1; k=rsa; p=..."
# DMARC
_dmarc.yourdomain.com TXT "v=DMARC1; p=quarantine; rua=mailto:[email protected]"
# Autoconfig (for Thunderbird)
autoconfig.yourdomain.com CNAME mail.yourdomain.com
# Autodiscover (for Outlook)
autodiscover.yourdomain.com CNAME mail.yourdomain.com
Post-Install Configuration
Access Admin Panel
Navigate to https://mail.yourdomain.com and log in with admin / password you set during installation.
Add Domains
Admin → Domains → Add Domain. Enter your domain name and Modoboa creates the necessary Postfix and Dovecot configurations automatically.
Generate DKIM Keys
Admin → Domains → select domain → DKIM → Generate key. Copy the public key and add it to DNS as a TXT record.
Create User Accounts
Admin → Domains → select domain → Mailboxes → Add account. Users can access webmail immediately at the server URL.
Modoboa Features
| Feature | Included | Notes |
|---|---|---|
| Multi-domain hosting | Yes | Unlimited domains |
| Webmail | Yes | Roundcube-based |
| Calendar/Contacts | Yes | Via Radicale plugin |
| Anti-spam | Yes | Rspamd or SpamAssassin |
| Virus scanning | Optional | ClamAV (needs 2GB RAM) |
| Auto-reply | Yes | Built-in |
| Autoconfig/Autodiscover | Yes | Automatic client setup |
| API | Yes | REST API for automation |
| DKIM management | Yes | Per-domain key generation |
Resource Comparison
| Platform | Min RAM | Docker Required | Web UI Quality |
|---|---|---|---|
| Modoboa | 1 GB | No | Good |
| Mailcow | 2 GB | Yes | Excellent |
| iRedMail | 2 GB | No | Basic (free) |
| Mail-in-a-Box | 1 GB | No | Basic |
Modoboa wins on resources. If you're running on a $4-6/month VPS and Docker overhead is a concern, it's the best option with a web admin panel.
Practitioner note: I've deployed Modoboa for clients who needed a mail server on existing infrastructure where Docker wasn't an option (company policy or legacy systems). It installs cleanly alongside other services as long as you manage the Nginx config carefully. Mailcow can't do that — it owns the entire server.
Maintenance
- Updates: Pull the latest installer and re-run, or update Modoboa via pip
- Backups: Back up
/var/vmail/(mailboxes), the PostgreSQL/MySQL database, and/etc/postfix/configs - Monitoring: Check Rspamd web UI for spam stats, review Postfix logs in
/var/log/mail.log - SSL renewal: Let's Encrypt auto-renews via certbot; verify monthly
# Check for Modoboa updates
pip install --upgrade modoboa
# Apply database migrations
cd /srv/modoboa && python manage.py migrate
Practitioner note: Modoboa's smaller community means fewer Stack Overflow answers and forum threads when you hit issues. Budget extra troubleshooting time compared to Mailcow. The documentation is decent but not as comprehensive. If you're comfortable reading Django error logs, you'll be fine.
If you're evaluating Modoboa against other self-hosted options, schedule a consultation — I'll compare platforms against your specific requirements and budget.
Sources
- Modoboa: Official Documentation
- Modoboa: GitHub Repository
- Modoboa: Installer Repository
- Rspamd: Documentation
v1.0 · April 2026
Frequently Asked Questions
Is Modoboa free?
Yes. Modoboa is open-source under the ISC license. All core features are free — domain management, user accounts, webmail, anti-spam. Some plugins and the hosted installer are paid.
What's the difference between Modoboa and Mailcow?
Modoboa installs on bare metal (no Docker), is Python/Django-based, uses less RAM (1GB vs 2GB+), and has a smaller community. Mailcow uses Docker, has a larger community, more integrations, and a more polished UI. Mailcow is better for most use cases unless you're resource-constrained.
How much RAM does Modoboa need?
1GB minimum for a small deployment (a few domains, low volume). 2GB recommended if you enable ClamAV for virus scanning. Without ClamAV, Modoboa runs comfortably on a $4/month VPS.
Can Modoboa handle multiple domains?
Yes. Multi-domain support is a core feature. Each domain gets its own DKIM keys, user management, and domain-level settings through the web admin panel.
Does Modoboa support Rspamd?
Yes. The Modoboa installer supports both SpamAssassin and Rspamd. Rspamd is recommended — it's faster, more modern, and provides better spam detection with a web UI for tuning.
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