Mike Hillyer
2.5 KiB
Traffic Shaping
By default, the KumoMTA server will deliver messages as quickly as possible to each destination, with few restrictions regarding number of connections, number of messages per connection, or number of messages per second. Because unthrottled sending is unwelcome by most MailBox Providers (MBPs) it is highly recommended that KumoMTA users implement traffic shaping in order to limit sending speeds to something more aligned with the expectations of the individual MBPs.
Common throttles include concurrent connection limits, messages per connection, rate of opening connections, and rate of sending messages. In addition, users can set options for various timeouts, queue sizes, and what encryption rules to use when communicating with remote hosts.
The shaping.lua Helper
While users are free to implement their traffic shaping rules as they see fit, the KumoMTA team has provided the shaping.lua helper as a pre-built implementation based on static configuration files in either JSON or TOML format, with support for various configuration scopes and automated rules using Traffic Shaping Automation.
The remainder of this chapter is focused on the use of the shaping.lua helper.
Traffic Shaping Automation
Many of the largest MailBox Providers (MBPs) operate platforms that provide feedback to senders through their response codes during the SMTP conversation. This feedback will include information related to the traffic shaping patterns in use by the sending including bounces for too many connections, too many messages per connection, sending rate, and sender reputation.
To ensure optimum throughput and deliverability, KumoMTA features Traffic Shaping Automation (TSA) that monitors responses from the MBPs and adjusts traffic shaping rules on a granular level to ensure compliance with the guidelines of the MBPs in realtime.
In This Chapter
- Scoping Traffic Shaping Rules — How KumoMTA uses domain, egress source, and site name to scope traffic shaping rules.
- Traffic Shaping Configuration Files — Configuring shaping rules using the
shaping.luahelper and TOML/JSON configuration files. - Traffic Shaping Automation — Deploying the TSA daemon for automated, real-time traffic shaping adjustments.