Postfix is a free, open-source mail transfer agent (MTA) that routes and delivers electronic mail. Designed as a secure, high-performance alternative to Sendmail, Postfix has become the industry standard MTA for Linux and Unix-like systems.
- Latest Stable: 3.10.8 (February 2026)
- Legacy Releases: 3.9.9, 3.8.15, 3.7.20
- Release Announcements: https://www.postfix.org/announcements.html
- High Performance: Efficient mail delivery with low resource usage
- Security-Focused: Designed with security as a primary concern
- Easy Configuration: Simpler configuration than Sendmail
- Sendmail Compatible: Drop-in replacement for Sendmail
- Robust Security: Privilege separation, chroot jail support
- Flexible Routing: Sophisticated mail routing capabilities
- TLS Support: Encrypted communication (SMTPS, STARTTLS)
- Anti-Spam Integration: Works with SpamAssassin, Rspamd, etc.
- Virtual Domains: Support for virtual mailbox domains
- Database Backends: MySQL, PostgreSQL, LDAP, SQLite support
- Internet Mail Servers: Primary MTA for organizations
- Mail Relay: Secure outbound mail relay
- Virtual Hosting: Multi-domain mail hosting
- Gateway Services: Mail filtering and routing gateway
- Development/Testing: Local mail delivery for applications
- Language: C
- Architecture: Modular with separate components for different tasks
- OS Support: Linux, BSD, macOS, Solaris, other Unix-like systems
- Dependencies: Standard Unix libraries, OpenSSL/TLS for encryption
- Primary: IBM Public License 1.0 (IPL 1.0)
- Alternative: Eclipse Public License 2.0 (EPL 2.0)
- Dual License: Since Postfix 3.2.5, users can choose either license
- ✅ Actively Maintained - Regular stable releases
- ✅ Industry Standard - Default MTA for most Linux distributions
- ✅ Production Ready - Used by millions of servers worldwide
- ✅ Long History - In development since 1998
Postfix can run in Docker containers, though there’s no official Docker image. Popular community images include:
- juanluisbaptiste/postfix: Simple SMTP relay
- eeacms/postfix: Rocky Linux-based relay
- boky/postfix: Full-featured Postfix
- catatnight/postfix: Lightweight relay
# Example: Simple Postfix relay
docker run -d \
--name postfix \
-e SMTP_RELAY_SERVER=smtp.example.com:587 \
juanluisbaptiste/postfix:latest
👉 Full Docker Setup
Postfix uses a modular architecture with separate components:
┌─────────────────────────────────────────┐
│ Postfix MTA │
├─────────────────────────────────────────┤
│ ┌──────────┐ ┌──────────┐ ┌────────┐ │
│ │ master │ │ pickup │ │ cleanup│ │
│ │ (manager)│ │ (local) │ │ (queue)│ │
│ └──────────┘ └──────────┘ └────────┘ │
│ ┌──────────┐ ┌──────────┐ ┌────────┐ │
│ │ qmgr │ │ smtp │ │ local │ │
│ │ (queue) │ │ (deliver)│ │(deliver)││
│ └──────────┘ └──────────┘ └────────┘ │
└─────────────────────────────────────────┘
¶ History and References
- Official Website: https://www.postfix.org/
- Documentation: https://www.postfix.org/documentation.html
- Mailing List: postfix-users@postfix.org
- IRC: #postfix on Libera.Chat
Common issues and solutions:
- Mail not sending: Check mail logs (
/var/log/mail.log)
- Relay access denied: Configure
mynetworks properly
- TLS issues: Verify certificate paths and permissions
- Queue problems: Use
mailq, postqueue -f commands
👉 See Postfix Configuration for detailed configuration guidance.
Any questions?
Feel free to contact us. Find all contact information on our contact page.