How to Install PowerMTA on AlmaLinux 8/9

AlmaLinux is a solid choice for email servers. It's a free, community-driven replacement for CentOS and works perfectly with PowerMTA. Whether you're on AlmaLinux 8 or 9, this guide has you covered.

Want to skip the manual setup? PMTAcore's PowerMTA Installer can do all of this automatically. But if you like getting your hands dirty, let's get into it.

Prerequisites

Here's what you need before starting:

• A clean AlmaLinux 8 or 9 server with at least 2GB RAM
• Root access or a user with sudo privileges
• A valid PowerMTA license
• A domain name with DNS access
• Port 25 unblocked by your hosting provider

Step 1: System Update and Dependencies

Start by bringing your system up to date and installing the tools you'll need:

sudo dnf update -y
sudo dnf install -y wget curl nano tar bind-utils

The bind-utils package gives you dig and nslookup, which are handy for DNS troubleshooting later.

Step 2: Disable SELinux (Optional but Recommended)

SELinux can interfere with PowerMTA's operation. You can either configure it properly or set it to permissive mode:

sudo setenforce 0
sudo sed -i 's/SELINUX=enforcing/SELINUX=permissive/' /etc/selinux/config

If you're running a production server, consider writing proper SELinux policies instead of disabling it entirely.

Step 3: Set the Hostname

Your hostname should match your mail domain's rDNS record. This is critical for deliverability.

sudo hostnamectl set-hostname mail.yourdomain.com

Also update /etc/hosts:

echo "YOUR_SERVER_IP mail.yourdomain.com" | sudo tee -a /etc/hosts

Step 4: Install PowerMTA

Transfer your PowerMTA RPM to the server and install it:

# For AlmaLinux 8
sudo rpm -ivh pmta-5.x.x-x.el8.x86_64.rpm

# For AlmaLinux 9
sudo rpm -ivh pmta-5.x.x-x.el9.x86_64.rpm

Make sure you're using the correct RPM for your AlmaLinux version. Using the wrong one will cause dependency errors.

Step 5: License Setup

sudo cp license.txt /etc/pmta/license
sudo chown pmta:pmta /etc/pmta/license
sudo chmod 644 /etc/pmta/license

Step 6: Configure PowerMTA

Edit the main config file at /etc/pmta/config:

postmaster postmaster@yourdomain.com

smtp-listener 0.0.0.0:25

<source 0/0>
  always-allow-relaying yes
  smtp-service yes
</source>

<domain *>
  use-starttls yes
  require-starttls no
  max-smtp-out 20
  retry-after 10m
  bounce-after 4d12h
</domain>

For a production setup, you'll want to add DKIM, SPF, and DMARC records. We have a dedicated guide on setting up DKIM, SPF, and DMARC with PowerMTA.

Step 7: Open Firewall Ports

sudo firewall-cmd --permanent --add-service=smtp
sudo firewall-cmd --permanent --add-port=587/tcp
sudo firewall-cmd --permanent --add-port=8080/tcp
sudo firewall-cmd --reload

Step 8: Start and Enable PowerMTA

sudo systemctl start pmta
sudo systemctl enable pmta
sudo pmta show status

If everything is working, you'll see the PowerMTA version and status output.

Step 9: Test Your Setup

echo "Hello from AlmaLinux" | pmta inject --from test@yourdomain.com --to your-email@gmail.com

Check your inbox. If the email lands in spam, don't worry — that's normal without proper DNS authentication. Setting up DKIM and SPF will fix that.

AlmaLinux 8 vs 9: Key Differences

• Package manager: Both use dnf, but AlmaLinux 9 has newer default packages
• Firewall: Both use firewalld, same commands work on both
• OpenSSL: AlmaLinux 9 ships with OpenSSL 3.x, which may affect TLS configuration
• RPM compatibility: Use the correct RPM build for your version — el8 for AlmaLinux 8, el9 for AlmaLinux 9

Troubleshooting

• PowerMTA won't start: Check /var/log/pmta/log for error messages. Most common issue is a missing or invalid license.
• Connection refused on port 25: Verify your firewall rules and check if your provider blocks SMTP traffic.
• Emails bouncing: Make sure your rDNS, SPF, and DKIM are all configured correctly.

Automate Everything with PMTAcore

Setting up PowerMTA manually works, but it takes time and there's room for error. PMTAcore handles the entire process automatically — from installation to DNS configuration to ongoing monitoring.

With PMTAcore, you get:

• One-click PowerMTA installation on AlmaLinux, Rocky Linux, CentOS, and more
• Automatic DNS setup including DKIM, SPF, and DMARC
• Real-time IP blacklist monitoring
• Cloud server management across multiple providers

Download PMTAcore today or explore our pricing options to find the right plan for you.