How to Set Up Postal SMTP Server on Linux

By Admin · Mar 1, 2026 · Updated Apr 24, 2026 · 30 views · 2 min read

What Is Postal?

Postal is an open-source mail delivery platform designed for sending transactional and bulk emails. It provides a web interface for tracking deliveries, managing domains, and monitoring bounce rates. Postal is a strong self-hosted alternative for outbound email from your Breeze.

Prerequisites

A Breeze with at least 4 GB RAM running Ubuntu 22.04+
Docker and Docker Compose installed
A domain with proper DNS records
Port 25 open for outbound SMTP

Step 1: Clone and Configure Postal

git clone https://github.com/postalserver/install /opt/postal/install
sudo ln -s /opt/postal/install/bin/postal /usr/bin/postal
postal bootstrap postal.yourdomain.com

Step 2: Edit the Configuration

nano /opt/postal/config/postal.yml

Key settings to configure:

web:
  host: postal.yourdomain.com
  protocol: https
smtp_server:
  port: 25
  tls_enabled: true
dns:
  mx_records:
    - mx.postal.yourdomain.com
  spf_include: spf.postal.yourdomain.com
  return_path_domain: rp.postal.yourdomain.com

Step 3: Initialize and Start

postal initialize
postal make-user
postal start

Step 4: Configure DNS

Add these DNS records for your sending domain:

SPF: v=spf1 a mx include:spf.postal.yourdomain.com -all
Return Path: CNAME rp.postal.yourdomain.com
DKIM: Add the TXT record from the Postal web interface under your domain settings

Step 5: Access the Dashboard

Navigate to https://postal.yourdomain.com and log in with the credentials created during make-user. From the dashboard you can add organizations, create mail servers, and generate API credentials for sending.

Tips

Monitor delivery stats and bounces from the web dashboard
Set up webhook endpoints to receive delivery notifications
Use IP warm-up if sending volume from your Breeze is new