Powermta Domain Detail -
<virtual-mta domain-specific> bind-to-source-ip 192.168.1.100 <domain example.com> max-smtp-out 10 </domain> <domain gmail.com> max-smtp-out 20 route alt4.gmail-smtp-in.l.google.com:25 </domain> </virtual-mta> <domain yahoo.com> max-smtp-out 2 # total connections max-smtp-out-per-ip 1 # per destination IP smtp-pipeline-depth 5 # pipelined commands delivery-interval 10 # seconds between connection attempts 5. Routing & Failover Domains Smart host routing:
<domain att.net> route smtp.att.net:25 route backup-relay.att.net:25 weight=2 fallback-to-mx yes </domain> powermta domain detail
PowerMTA (PMTA) treats domains as critical routing and policy endpoints. Unlike generic MTAs, PMTA separates the envelope domain (SMTP conversation) from the policy domain (rules). These are set within a <domain> block or global defaults. <domain> example.com ... Defines a specific domain configuration block. All settings inside apply only to this recipient domain. <virtual-mta domain-specific> bind-to-source-ip 192
log-domain /var/log/pmta/domains/%d.log # %d expands to domain name Then within <domain> : These are set within a <domain> block or
This covers the essential domain-level configuration in PowerMTA. For a specific use case (e.g., Gmail, Yahoo, custom smart host), the route , max-smtp-out , and DKIM settings become most critical.
<domain mylocal.com> local yes mailbox-command /usr/bin/procmail </domain> Enable domain-specific logging in <source> or global log-domain :
| Directive | Purpose | Example | |-----------|---------|---------| | max-smtp-out | Max concurrent outbound connections to this domain | max-smtp-out 5 | | smtp-port | Override default port (25) | smtp-port 587 | | route | Force traffic through a specific smart host | route smtp.relay.com | | resolve-to | Rewrite destination MX lookup | resolve-to 10.0.0.1 | | max-message-size | Max email size for this domain | max-message-size 25M | | require-rdns | Require reverse DNS for incoming connections | require-rdns yes | | dkim-sign | Enable DKIM signing for this domain (see below) | dkim-sign yes | | tls | Enforce TLS | tls required | PowerMTA signs emails per domain using domain-key files.