📄️ Overview
Stalwart Mail Server provides administrators with the ability to configure various constraints on message intake and delivery. These limits include rate limiting, quotas, and concurrency limits, offering a comprehensive toolkit to manage the server's performance and security.
📄️ Threads
Stalwart maintains a pool of delivery threads that are used to send messages both locally and to remote SMTP servers. It is important to configure the number of delivery threads to ensure that the server can handle the required load. A number too low can result in slow message delivery, while a number too high can lead to high memory usage and CPU load.
📄️ Rate Limits
Rate limiting is a mechanism used to control the flow of connections and messages by restricting the number of requests or actions allowed over a specific time period. In Stalwart Mail Server, rate limiting ensures that email traffic is managed efficiently, preventing resource overuse and protecting the server from abuse, such as spam or denial-of-service (DoS) attacks.
📄️ Quotas
Quotas allows to set limits on the message queue to control its size and total number of messages. Stalwart Mail Server supports enforcing dynamic quotas on the message queue, which means that it can limit the total size and number of messages waiting to be delivered based on multiple variables. If a queue quota is exceeded, messages will be temporarily rejected with a 4xx SMTP code. This is useful in preventing the server from becoming overwhelmed by too many messages and ensuring that important messages are delivered promptly.