Message Acceptance Policies

The Axigen Solution: Overview & Architecture

Axigen implements a set of message acceptance rules at SMTP-connection level.

You can configure and implement message acceptance rules and adjust them to best suit your company's security requirements. Incoming connections established via SMTP and the message flow can be easily managed using the established rules. Moreover, they allow adding headers, changing addresses and other such actions.

Examples of message acceptance rules:

  • allow incoming messages from a specific domain
  • deny incoming messages with attachments exceeding 3 MB
  • allow authenticated users only
  • accept secured connections only
  • deny looping emails (when the number of Received headers exceeds 20)

The message acceptance rules can consist in any number of such rules applied following a given priority. These rules can be set at SMTP Incoming level and help save space and resources for email processing.

The rules are defined using an Axigen proprietary scripting language and are at this time contained, along with the Processing and Relay policy scripts, in a single file per installed server named smtpFilters.script. They can also be created automatically via the WebAdmin Wizard.

Through the message acceptance rules, a wide range of event handlers associated with the SMTP events are available, along with various methods, message headers, envelopes and peer information.

The events are predefined blocks within the script that will be executed at specific moments by the server. For each event, the server calls certain methods which can have a configurable or predefined behavior. The available events at SMTP Incoming level are:

  • onConnect
  • onEhlo
  • onMailFrom
  • onRcptTo
  • onHeadersReceived
  • onBodyChunk
  • onDataReceived

Message acceptance rules are based on a proprietary scripting language.