SMTP

Push

Synopsis

Creates an SMTP server that receives email messages. Supports authentication, TLS encryption, and multiple workers with automatic message handling, and JSON conversion.

Schema

- id: <numeric>
  name: <string>
  description: <string>
  type: smtp
  tags: <string[]>
  pipelines: <pipeline[]>
  status: <boolean>
  properties:
    address: <string>
    port: <numeric>
    username: <string>
    password: <string>
    timeout: <numeric>
    reuse: <boolean>
    workers: <numeric>
    buffer_size: <numeric>
    tls:
      status: <boolean>
      cert_name: <string>
      key_name: <string>

Configuration

The following fields are used to define the device:

Device

Field	Required	Default	Description
id	Y		Unique identifier
name	Y		Device name
description	N	-	Optional description
type	Y		Must be smtp
tags	N	-	Optional tags
pipelines	N	-	Optional pre-processor pipelines
status	N	true	Enable/disable the device

Connection

Field	Required	Default	Description
address	N	"0.0.0.0"	Listen address
port	Y		Listen port
username	N	-	Authentication username
password	N	-	Authentication password
timeout	N	15	Connection timeout in seconds

TLS

Field	Required	Default	Description
tls.status	N	false	Enable TLS encryption
tls.cert_name	Y		TLS certificate file path (required if TLS enabled)
tls.key_name	Y		TLS private key file path (required if TLS enabled)

note

The TLS certificate and key files must be placed in the service root directory.

Performance

Field	Required	Default	Description
reuse	N	false	Enable multi-worker mode
workers	N	4	Number of worker processes when reuse enabled
buffer_size	N	9000	Read buffer size in bytes

Key Features

The following are unique features that Director offers.

Emails

The server captures and processes email headers, sender information, recipient information, message content, attachments, and remote client information.

JSON Conversion

All email messages are automatically converted to JSON format with the following fields:

Field	Description
from	Sender address
to	Recipient addresses
subject	Email subject
body	Message body
headers	Email headers
remoteAddr	Client IP address

Multiple Workers

When reuse is enabled, the server uses multiple worker processes which maintain a separate SMTP listener and process messages independently. Messages are automatically converted to JSON.

note

The worker count will be capped at the number of available CPU cores.

Examples

The following are commonly used configuration types.

Basic

A basic server can be easily created:

Creating a simple SMTP server...

devices: - id: 1 name: basic_smtp type: smtp properties: address: "0.0.0.0" port: 25

Secure

E-mail can be received securely:

Configuring TLS and authentication...

devices: - id: 2 name: secure_smtp type: smtp properties: address: "0.0.0.0" port: 587 username: "mailuser" password: "secret" timeout: 30 tls: status: true cert_name: "smtp.crt" key_name: "smtp.key"

note

Port 587 is commonly used for TLS-enabled SMTP (STARTTLS).

High-Volume

Performance can be enhanced for high email volumes:

Optimizing for high message volumes...

devices: - id: 3 name: performant_smtp type: smtp properties: address: "0.0.0.0" port: 25 timeout: 60 reuse: true workers: 4 buffer_size: 32768

Submissions

Message submission can be dedicated:

Configuring a message submission server...

devices: - id: 4 name: submission_smtp type: smtp properties: address: "0.0.0.0" port: 587 username: "mailuser" password: "secret" timeout: 30 tls: status: true cert_name: "smtp.crt" key_name: "smtp.key" reuse: true workers: 2

Pipelines

Emails can be pre-processed:

Applying custom processing to emails...

devices: - id: 5 name: pipeline_smtp type: smtp pipelines: - email_parser - spam_filter properties: address: "0.0.0.0" port: 25 timeout: 30

note

Pipelines are processed sequentially and can modify or drop messages before ingestion.