Hot - Sample Powermta Configuration File

A standard configuration consists of several core sections: global settings, listener settings, and Virtual MTA (VMTA) definitions.  1. Global and Network Settings 

These define basic identity, file paths, and administrative access. 

# General Identification host-name yourdomain.com postmaster postmaster@yourdomain.com # HTTP Management Console (Port 8080) http-mgmt-port 8080 http-access 1.2.3.4 monitor # Allow only your IP to monitor http-access 127.0.0.1 admin # Log File Paths log-file /var/log/pmta/pmta.log acct-file /var/log/pmta/acct.log Use code with caution. Copied to clipboard 2. SMTP Listener (Injection) 

This section defines how your applications or users connect to PowerMTA to send emails. 

# SMTP Listener on all IPs, port 25 and 587 smtp-listener 0.0.0.0:25 smtp-listener 0.0.0.0:587 password "YOUR_SECURE_PASSWORD" authentication-method password # Source configuration for local/authorized senders always-allow-relaying yes process-x-virtual-mta yes Use code with caution. Copied to clipboard 3. Virtual MTA (Delivery)  sample powermta configuration file hot

This is where you define the specific IPs and domains used for sending. 

# Virtual MTA for a specific IP smtp-source-ip 1.2.3.4 host-name ://yourdomain.com domain-key selector1, yourdomain.com, /etc/pmta/dkim.private.key # Virtual MTA Pool for load balancing multiple IPs virtual-mta vmta1 virtual-mta vmta2 Use code with caution. Copied to clipboard 4. Domain Directives (Rate Limiting) 

These settings control delivery speeds to specific ISPs like Gmail or Yahoo to prevent blocking. 

# Default limits for all domains max-smtp-out 20 max-msg-per-connection 100 retry-after 10m # Specific limits for Gmail to avoid "too many connections" max-smtp-out 5 max-msg-rate 200/h Use code with caution. Copied to clipboard Essential Configuration Tips  A standard configuration consists of several core sections:

Keep it DRY (Don't Repeat Yourself): Use wildcard domains () for common settings and only specify overrides for large ISPs.

IP Warm-up: For "hot" or new configurations, use max-msg-rate to gradually increase volume and build sender reputation.

DKIM Signing: Ensure every Virtual MTA includes a domain-key directive pointing to a valid private key for authentication.

Troubleshooting: Use the command pmta debug to check for syntax errors or line number issues before restarting the service.  How to Install & Setup PowerMTA on CentOS 7 Logging settings

Here’s a solid, in-depth review of what a “sample PowerMTA configuration file” should look like — especially if you’re searching for a “hot” (high-performance, deliverability-focused) setup.

I’ll break down the key sections, explain what each does, and highlight what makes a config hot versus just functional.

Logging settings

• log_level: the logging level (one of "debug", "info", "notice", "warning", "error", "critical")
• log_file: the path to the log file

3. Source IP Binding

<source 192.0.2.10>
  process-x-forwarded-for no
  always-allow-relaying no
  max-smtp-in 200
</source>

• Controls inbound settings
• process-x-forwarded-for off for security

Important Disclaimer

Use this as a template. You must replace placeholders (like IPs, domains, and passwords) with your actual data. Always test a new configuration in a staging environment before applying it to production.

❌ Common “Cold” Mistakes in Sample Configs

• No DKIM or SPF setup
• max-smtp-out too high for Gmail/Yahoo → 550 rejects
• Missing ISP-specific throttling
• Single IP with no rotation
• No bounce handling logic
• Logging disabled – flying blind

Enable the HTTP management interface

http-mgmt-port 8080 http-access default allow

🚀 Pro Tips for a “Hot” Config

1. Pre-warm IPs – config won’t fix cold IP reputation
2. Split streams – separate vMTAs for warm vs. cold recipients
3. Monitor FBLs – integrate feedback loops
4. Use vmta-pool – round-robin IPs for large sends
5. Test throttling – start conservative, increase slowly