Mail-in-a-Box is a one-click mail server appliance designed for Ubuntu. It automates everything from DNS configuration to SSL certificates, making it easy to deploy a complete mail server with minimal configuration.
- Latest Release: v74 (January 4, 2026)
- First Release: 2013
- License: CC0-1.0 (Public Domain)
- Website: https://mailinabox.email/
- MTA: Postfix
- IMAP/POP3: Dovecot
- DNS: NSD4 (authoritative nameserver)
- Webmail: Roundcube
- Groupware: Nextcloud (CalDAV/CardDAV)
- ActiveSync: z-push
- Spam Filtering: SpamAssassin + Postgrey
- Antivirus: ClamAV (optional)
- Web Server: Nginx
- SSL: Automatic Let’s Encrypt
- One-Click Setup: Fully automated installation
- DNS Configuration: Automatic SPF, DKIM, DMARC, DNSSEC
- SSL Certificates: Automatic Let’s Encrypt
- Health Monitoring: Daily service status checks
- Backup System: Automated backups to cloud storage
- Control Panel: Web-based administration
- API: Full REST API for automation
- Personal Email: Self-hosted personal email
- Small Business: Simple business email
- Privacy-Focused: Escape big tech email providers
- Ubuntu Environments: Ubuntu-only deployments
- Appliance Style: Set-and-forget deployments
| Component |
Technology |
| MTA |
Postfix |
| IMAP/POP3 |
Dovecot |
| DNS |
NSD4 |
| Web Server |
Nginx |
| Webmail |
Roundcube |
| Groupware |
Nextcloud |
| ActiveSync |
z-push |
| Spam Filter |
SpamAssassin + Postgrey |
| SSL |
Let’s Encrypt (automatic) |
| Backup |
Duplicity |
- OS: Ubuntu 22.04 LTS 64-bit ONLY
- Installation: Fresh OS installation required
- Architecture: 64-bit (x86_64)
- CPU: 1 core (2+ recommended)
- RAM: 1 GB minimum (2+ GB recommended)
- Storage: 20 GB+ (depends on mailbox needs)
- Network: Static IP address
- ⚠️ Ubuntu Only: Does not support other distributions
- ⚠️ Fresh Install: Requires clean Ubuntu installation
- ⚠️ No Upgrades: In-place OS upgrades not supported
- ✅ Simple: Designed for simplicity over flexibility
- CC0-1.0: Public Domain / No Rights Reserved
- Components: Various open-source licenses
- ✅ Actively Maintained - Regular releases
- ✅ Production Ready - Used by thousands
- ✅ Simple Setup - One-command installation
- ⚠️ Ubuntu Only - No other OS support
- ⚠️ Opinionated - Limited configuration options
| Method |
Description |
Best For |
| Traditional Setup |
One-command Ubuntu installer |
Production, Ubuntu deployments |
| Ansible Setup |
Automated deployment with Ansible |
IaC, automated deployments |
Note: Mail-in-a-Box does not officially support Docker deployment.
Mail-in-a-Box uses a single installation command:
# Download and run installer
curl -s https://mailinabox.email/setup.sh | sudo bash
The installer will:
- Install all required packages
- Configure Postfix, Dovecot, Nginx
- Set up DNS server (NSD4)
- Obtain SSL certificates
- Configure DNS records (SPF, DKIM, DMARC, DNSSEC)
- Install Roundcube webmail
- Install Nextcloud for groupware
- Set up automated backups
┌─────────────────────────────────────────────────────┐
│ Mail-in-a-Box Appliance │
├─────────────────────────────────────────────────────┤
│ ┌──────────┐ ┌──────────┐ ┌──────────┐ │
│ │ Postfix │ │ Dovecot │ │ NSD4 │ │
│ │ (MTA) │ │ (IMAP) │ │ (DNS) │ │
│ └──────────┘ └──────────┘ └──────────┘ │
│ ┌──────────┐ ┌──────────┐ ┌──────────┐ │
│ │ Roundcube│ │ Nextcloud│ │ Nginx │ │
│ │(Webmail) │ │(Groupware)│ │ (Web) │ │
│ └──────────┘ └──────────┘ └──────────┘ │
│ ┌──────────┐ ┌──────────┐ ┌──────────┐ │
│ │ z-push │ │SpamAssn │ │Let's Enc │ │
│ │(ActiveSyn)│ │ (Spam) │ │ (SSL) │ │
│ └──────────┘ └──────────┘ └──────────┘ │
└─────────────────────────────────────────────────────┘
Automated Appliance
The web-based control panel provides:
- User Management: Create/delete mailboxes
- Alias Management: Email aliases and forwards
- DNS Records: View required DNS records
- SSL Certificates: Certificate status
- Backup Configuration: Cloud backup setup
- Health Checks: Service status monitoring
- Custom DNS: Add custom DNS records
- API Access: Full REST API
Mail-in-a-Box automatically configures:
| Record Type |
Purpose |
| A |
Mail server IP address |
| MX |
Mail exchange record |
| SPF |
Sender Policy Framework |
| DKIM |
DomainKeys Identified Mail |
| DMARC |
Email authentication policy |
| DNSSEC |
DNS security extensions |
| MTA-STS |
Mail transfer security |
| TLSA |
DANE TLS authentication |
¶ History and References
- Official Website: https://mailinabox.email/
- Documentation: https://mailinabox.email/docs.html
- Discussion Forum: https://discourse.mailinabox.email/
- GitHub: https://github.com/mail-in-a-box/mailinabox
- Twitter: @mailinabox
Common issues and solutions:
- Port 25 blocked: Some VPS providers block SMTP; contact provider
- DNS issues: Ensure nameservers point to box
- SSL failures: Check DNS propagation
- Backup failures: Verify cloud storage credentials
👉 See Mail-in-a-Box Configuration for detailed configuration guidance.
Any questions?
Feel free to contact us. Find all contact information on our contact page.