Knowledge base
A new address without an external scheduler
Warm-up expressed as configuration
The task. An address added to the fleet must carry a small and growing share of traffic — and this must be expressed in the configuration, not in what is submitted from outside and how.
What it is made of:
- virtual-mta in <virtual-mta-pool> — the new address’s share in the pool in steps of 0.1 percent; the shares add up to 100;
- max-smtp-msg-rate in <virtual-mta> — the rate ceiling for the address as a whole, however much the share lets through;
- source-ip-max-msg-rate — the address’s rate per recipient;
- enable-source-ip-limits-on-sending-ip — so that per-address limits count the address the receiver sees, if sending goes through a proxy.
The parts have different scopes. The share belongs to the pool, the ceiling to the sending address, the rate to the recipient: three scopes for one warm-up stage.
How they interact. The share decides how much mail is offered, the address ceiling limits what is accepted, and the per-recipient rate decides how it is delivered. Any part alone leaves a hole: a share without a ceiling lets a burst through, a ceiling without a per-recipient rate gives everything to one receiver.
The main trap is a share alone without a rate ceiling. A share in the pool sets a proportion, not a volume: on the day of a big campaign, 0.1 percent of it can be more than a cold address can withstand — only max-smtp-msg-rate holds the volume.
What the Hub does. It does not apply it: the Hub runs warm-up externally — the scheduler keeps the daily volume, and the engine gets max-smtp-out 1 and the rate in the WARMUP-MANAGED block, which warm-up rewrites itself. There are no pool weights, no address rate ceiling and no per-receiver address rate.
Recommended values
Three scopes of one stage:
| What | Line | Where | Stage example |
|---|---|---|---|
| traffic share | virtual-mta with a percentage | <virtual-mta-pool> | 0.1, then 1, then 5 |
| address ceiling | max-smtp-msg-rate | <virtual-mta> | 500/d |
| per-recipient rate | source-ip-max-msg-rate | <domain> | 50/h |
Pool shares in steps of 0.1 summing to 100, the address ceiling and the per-recipient rate come from the manual (§ 3.3.13.1, § 3.3.12.2, § 3.3.10.93, § 3.3.10.86). The scheme itself and the stage numbers are our hypothesis.
Example configuration
<virtual-mta-pool main> virtual-mta vmta-settled 99.9 virtual-mta vmta-new 0.1</virtual-mta-pool> <virtual-mta vmta-new> max-smtp-msg-rate 500/d </virtual-mta>
The shares are as in the manual’s example; the ceiling holds the volume even if the share lets more through.
yellow — — directive names, blue — blocks. They are highlighted the same way in the text of the card.
Compatibility
PowerMTA 6.0
described in the manual of this version · platform: any
The vendor does not state the first version for every directive — there is no note here. The name also appears in the 5.0 edition of the manual.
How to check on the node
Check the new address’s effective ceiling:
pmta show settings gmail.com/vmta-new | grep '^max-smtp-msg-rate '
unlimited — only the share holds the stage, and the volume is not limited by anything.