Demo
Demo

Knowledge base

PMTA knowledge base›Mechanism§ 2.6

A license for a fleet, not for a server

volume-based license
Volume is counted, not the number of machines

A license for virtual and cloud servers: it is not bound to a specific machine and is installed on as many servers as the “instances” limit in the license file allows.

It is installed like a regular one, but with a key, volume-audit-api-key, issued by SparkPost with the license: the node authenticates itself with it when sending statistics.

The node counts volume itself: every minute it collects the number of recipients in the queue and the number of inbound and outbound recipients, and sends them to the vendor every hour. This requires outbound access to api.pmta.sparkpost.com on port 443. Payment is annual, by the number of messages.

The main trap is closing outbound access to the vendor. A node with such a license sends statistics to api.pmta.sparkpost.com, port 443, every hour; the manual explicitly requires letting this address through the firewall.
What the Hub does. It does not touch this: the licenses on the nodes belong to clients, their type is unknown to the Hub, and the Hub does not write volume-audit-api-key.
Recommended values

What is where:

What Where
how many machines are allowed the “instances” limit in the license file
what the node authenticates with volume-audit-api-key
where statistics go api.pmta.sparkpost.com, port 443
Binding to the number of instances, the key, the statistics contents and the vendor address come from the manual (§ 2.6). The table is ours.
Example configuration
# the key for a volume-based license
volume-audit-api-key abcd0123skdju673jdksdkshd73j7shfk
SparkPost issues the key with the license; the line comes from the manual’s example.
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.
⇄

Related entries

4 relations

Does not work without

volume-audit-api-keyGlobalThe directive that enables this mechanism. § 2.6

Same name in other blocks

The activation key is a prerequisite for installation, not a step after itA related mechanism: they work together. § 2.6

Works together with

What makes a virtual machine riskyA related mechanism: they work together. § 2.6

Applies to

License fileThe file the mechanism is concerned with. § 2.6

Referenced from

License informationThe mechanism the command works with. § 6.3.30The vendor's analytics — and what leaves the node for itThe second outbound dependency on the vendor — next to the license check. inference

How to check on the node
Check the instance limit and access to the vendor:
pmta show license
nc -vz -w 5 api.pmta.sparkpost.com 443
The number in the “instances” line is the machine limit; the connection to the vendor address must go through.
◇

What else to read

3 articles

◇The activation key is a prerequisite for installation, not a step after itWithout an activation key from SparkPost support the engine neither installs nor runs, and the license tier sets the outbound connection ceiling: on Standard everything above 200 is ignored.◇Cloud restrictionsClouds restrict outbound mail on port 25 until you ask them to lift the limit, and mailbox providers treat their address ranges with suspicion.◇How to turn a sending plan into hardwareTwo constants for sizing any node: about 2 KB of memory per queued recipient and spool space proportional to the total size of the messages.

In the Hub
Cost of a mistake
safe: a wrong value breaks nothing
Scenarios
Capacity planning · Prepare a node for sending · Sender isolation