Powermta Configuration Guide Top |work| -

Modern email standards require a full suite of authentication protocols to ensure inbox placement. Time4Servers SPF (Sender Policy Framework) : A TXT record listing authorized sending IPs. DKIM (DomainKeys Identified Mail)

: Control who can submit mail to your PMTA. Restrict relaying to local or specific IP addresses to prevent becoming an open relay. > always-allow-relaying yes

Modern authentication is mandatory for inbox delivery. While SPF and DMARC are DNS-level configurations, DKIM signing is a key task for your MTA.

PowerMTA also supports directives, allowing you to split large configurations into manageable parts (e.g., one file for DKIM keys, another for ISP‑specific domain rules). This also facilitates the DRY (Don’t Repeat Yourself) principle, which is an official best practice for PowerMTA maintenance. powermta configuration guide top

# Allow local applications to inject mail without authentication always-allow-relaying yes process-x-envid yes # Require SMTP Authentication for remote marketing apps always-allow-relaying no smtp-auth username-password Use code with caution. 5. ISP-Specific Traffic Shaping and Throttling

The main configuration file resides at /etc/pmta/config . Before making extensive modifications, back up the original:

<virtual-mta vmta-pool> smtp-source-host 192.168.1.10 smtp-source-host 192.168.1.11 smtp-source-host 192.168.1.12 smtp-mail-host mail.mydomain.com max-smtp-out 30 domain-key default,mydomain.com,/etc/pmta/dkim/private.key </virtual-mta> Modern email standards require a full suite of

Effective bounce and complaint processing is the .

Use unique selectors (e.g., pmta2026 ) to allow seamless annual key rotation without disrupting active streams. 4. ISP-Specific Back-Off Configurations

The max-cold-virtual-mta-msg directive caps daily messages for recipients lacking prior engagement history: Restrict relaying to local or specific IP addresses

, you can load-balance traffic across multiple IPs, which helps prevent any single IP from hitting rate limits too quickly. 3. Traffic Control: The Domain Macro

Each major ISP requires custom tuning:

Create a TXT record for myselector._domainkey.example.com containing the public key material.

Example: