# Multi-VMTA hot configuration example virtual-mta pmta-newsletter-pool smtp-source-host 192.168.1.10 newsletter1.example.com smtp-source-host 192.168.1.11 newsletter2.example.com max-smtp-msg-rate 10000/h
: Thrives on a steady stream of traffic rather than massive bursts. The max-msg-rate 120/m keeps delivery smooth. 3. Virtual MTA Pooling ( virtual-mta-pool )
mail-from /@transactional.sender.org/ virtual-mta pmta-transactional-pool max-msg-rate 2000/h sample powermta configuration file hot
When IPs are fully warmed up, you can lift restrictive caps, but you should never remove them completely.
The change from defaults: max-per-host-out 100 . Standard config uses 20. Bumping to 100 allows simultaneous delivery to large ISPs like Gmail. However, never exceed 200—Google’s postmaster guidelines suggest 100-120 per IP. Bumping to 100 allows simultaneous delivery to large
When your PowerMTA configuration is dialed in, you achieve the holy grail of email infrastructure: maximum throughput with optimal deliverability—all while staying hot, responsive, and production-ready.
virtual-mta pmta-transactional-pool smtp-source-host 10.0.0.10 trans.example.com smtp-source-host 10.0.0.11 trans2.example.com Aggressive Retry Windows for Hot Traffic
The <source> block is a critical part of the configuration that is often overlooked. It defines which IP addresses (or CIDR ranges) are allowed to connect to your PowerMTA instance to submit mail. The sample config shows a secure setup:
Unlike banking emails, lifestyle emails have a . A concert invite is worthless 2 hours after the show starts. We adjust the queue management accordingly.
The sample utilizes a pool named pool-hot-delivery . By grouping multiple hot IPs ( vmta-hot-01 , vmta-hot-02 ) into a single pool, PowerMTA automatically load-balances out-bound mail across those IPs using a round-robin algorithm. This prevents a single IP from absorbing too much traffic and overheating. 4. Aggressive Retry Windows for Hot Traffic