Skip to main content

Prerequisites

Before you install and run LSMTPD, make sure your environment meets the basic requirements.
This ensures that the server can run smoothly and integrate correctly with your existing infrastructure.

System Requirements​

  • Operating System:

    • Linux (Debian/Ubuntu recommended for packaged install).
    • Other Linux distributions supported via Docker or source build.

  • Architecture:

    • x86_64 (amd64).
    • ARM64 (supported via Docker and source build).

  • Memory / CPU:

    • Very lightweight — runs comfortably in 128MB RAM / 1 vCPU environments.
    • Scales efficiently with additional resources.

Software Requirements​

  • AMQP Broker
    LSMTPD requires an AMQP-compatible message broker (e.g., RabbitMQ, Apache Qpid, or any AMQP 0.9.1/1.0 compliant broker).

    • Make sure your broker is installed, running, and reachable.
    • Have a queue or exchange ready to receive messages.

  • Rust toolchain (only if building from source)

    • If you plan to build from source, you’ll need Rust (latest stable release).
    • Building is not required if you use the Debian package or Docker image.

Network & Security Requirements​

  • SMTP Port Access

    • By default, LSMTPD listens on port 25 (standard SMTP).
    • If running as a non-root user, you may configure it to use a higher port (e.g., 2525).

  • Firewall Rules

    • Allow inbound SMTP traffic on the chosen port.
    • Ensure outbound connectivity to your AMQP broker (typically port 5672 or 5671 for TLS).

  • User Permissions

    • If binding to port 25, LSMTPD may need root privileges or systemd capabilities (CAP_NET_BIND_SERVICE).

Before using LSMTPD, you should be familiar with:

  • Basic SMTP concepts: how email clients connect and send mail.
  • AMQP fundamentals: queues, exchanges, and routing.
  • System administration basics: configuring services, opening firewall ports, and using logs.

Next Steps​

Once your environment is ready, continue to the next page to install LSMTPD via Debian package, Docker, or source build.