Powermta Configuration Guide Top !!install!! Jun 2026

Are you setting this up for or marketing traffic?

Configure the to route these structured logs back to your application.

Load-balance your traffic across multiple IPs to prevent overloading a single IP address.

smtp-source-ip 192.0.2.10 host-name ://yourdomain.com smtp-source-ip 192.0.2.11 host-name ://yourdomain.com virtual-mta vmta-marketing virtual-mta vmta-marketing-2 Use code with caution. powermta configuration guide top

# Define the conditions that trigger backoff backoff-to-normal-after 1h data-availability-check yes # Apply the profile via domain directives backoff-retry-profile standard-backoff # Trigger backoff on common rate-limiting responses backoff-trigger-pattern /rate limit|too many connections|throttled/i Use code with caution. 6. Authentication: DKIM, SPF, and DMARC

A Virtual MTA associates a specific outbound IP address with a specific hostname. This allows you to isolate marketing traffic from transactional traffic. Configuring a Standard VMTA

dkim-sign yes dkim-algorithm rsa-sha256 # Path to your private keys domain yourdomain.com selector pmta2026 key-file /etc/pmta/keys/yourdomain.com.pmta2026.pkcs8 Use code with caution. Are you setting this up for or marketing traffic

Allocate huge pages for queues:

This endpoint provides detailed information including queue sizes, active connections, and delivery status for each domain.

# Administrative Email Addresses postmaster postmaster@yourdomain.com bounce-to bounce-handler@yourdomain.com # Web Management Console Configuration http-mgmt-port 8080 http-access 127.0.0.1 allow http-access 192.168.1.0/24 allow http-access 0.0.0.0/0 deny # Logging and Spool Directories log-file /var/log/pmta/pmta.log spool-dir /var/spool/pmta Use code with caution. 2. Inbound Settings: Controlling Traffic Injection smtp-source-ip 192

However, a default installation of PowerMTA is like an un-tuned race car: it runs, but it won’t win. A misconfigured config file is the #1 reason for IP reputation damage, hard bounces, and being blacklisted.

Every sending IP must have a reverse DNS record matching your sending domain. Contact your hosting provider to configure:

<domain outlook.com> max-smtp-out 10 # Lower than Gmail. max-msg-rate 5/s max-msg-per-connection 20 use-starttls always # Microsoft penalizes rapid retries initial-pts 300 # 5 minutes on first temp fail. max-pts 7200 # 2 hours max penalty. # Honor their Junk Mail Reporting honor-dmarc-results true </domain>

# Syntax: domain-key <selector>,<domain>,<private-key-file> domain-key s1,client-b.com,/etc/pmta/dkim/client-b.key

dkim-sign yes dkim-key /etc/pmta/dkim/yourdomain.private dkim2026,yourdomain.com Use code with caution. External Records Checklist Ensure your DNS settings match your PowerMTA configuration: