n8n-nodes-terazone-smtp

Custom n8n community node for sending secure emails with file attachments via Terazone SMTP using a direct raw TCP connection.

Why a Custom Node?

n8n's built-in Code node runs in a sandboxed environment that blocks direct TCP socket connections (net.createConnection). Terazone SMTP requires a raw TCP connection with no TLS and no authentication — a custom node is the only way to achieve this within n8n.

Installation

From npm (recommended)

1. In your n8n instance, go to Settings > Community Nodes
2. Click Install a community node
3. Enter: n8n-nodes-terazone-smtp
4. Click Install

The node will be available immediately — no restart needed.

Manual Installation

# Navigate to your n8n user directory
cd ~/.n8n

# Install the package
npm install n8n-nodes-terazone-smtp

# Restart n8n

Credentials Setup

1. In n8n, go to Credentials > Add Credential
2. Search for "Terazone SMTP"
3. Fill in the following fields:

| Field | Type | Required | Default | Description | |---|---|---|---|---| | SMTP Host | string | Yes | — | Terazone SMTP server hostname | | SMTP Port | number | Yes | 25 | Terazone SMTP server port | | From Address | string | Yes | — | Sender email address used in MAIL FROM | | EHLO Domain | string | Yes | mail.example.com | Domain sent in the SMTP EHLO handshake | | Connection Timeout (ms) | number | No | 10000 | Maximum time to wait for the SMTP connection |

Node Parameters

| Parameter | Type | Required | Description | |---|---|---|---| | To Email | string | Yes | Recipient email address. Comma-separated for multiple recipients. | | Subject | string | Yes | Email subject line. | | Body | string | No | Plain text email body. | | Phone Numbers | string | No | Comma-separated phone numbers. Appended to the subject as #phone# identifiers for tracking. | | Attachment Source | select | Yes | Choose between Binary Property or Base64 String. | | Binary Property Name | string | Conditional | Name of the binary property from a previous node (shown when source = Binary Property). Default: data. | | Attachment File Name | string | Conditional | File name including extension (shown when source = Base64 String). | | Attachment Base64 Content | string | Conditional | Base64-encoded file content (shown when source = Base64 String). |

Usage Examples

Example 1: Send a simple test email

Use a Manual Trigger connected to the Terazone Secure Mail node with these settings:

• To Email: [email protected]
• Subject: Test from n8n
• Body: This is a test email
• Phone Numbers: 0501234567
• Attachment Source: Base64 String
• Attachment File Name: test.txt
• Attachment Base64 Content: SGVsbG8gV29ybGQ=

The SGVsbG8gV29ybGQ= value is "Hello World" in base64. The resulting subject will be: Test from n8n #0501234567#.

Example 2: Send a PDF from an HTTP Request

[Manual Trigger] → [HTTP Request] → [Terazone Secure Mail]

1. HTTP Request node: download a PDF with Response Format set to File
2. Terazone Secure Mail node:
   • Attachment Source: Binary Property
   • Binary Property Name: data

The node automatically reads the file name and base64 content from the binary data.

Example 3: Dynamic input from previous node

All parameters support n8n expressions. Connect a Set node or any data source:

• To Email: {{ $json.toEmail }}
• Subject: {{ $json.subject }}
• Body: {{ $json.body }}
• Phone Numbers: {{ $json.phoneNumbers }}
• Attachment File Name: {{ $json.attachmentFileName }}
• Attachment Base64 Content: {{ $json.attachmentBase64 }}

Sample input JSON for testing:

{
  "toEmail": "[email protected]",
  "subject": "Monthly report for January 2025",
  "body": "Hello, please find the attached report.",
  "phoneNumbers": "0501234567",
  "attachmentFileName": "test-result.txt",
  "attachmentBase64": "SGVsbG8gV29ybGQ="
}

Output

On success the node outputs:

{
  "success": true,
  "to": ["[email protected]"],
  "subject": "Test from n8n #0501234567#",
  "attachmentFileName": "test.txt"
}

On failure (with Continue On Fail enabled):

{
  "success": false,
  "error": "SMTP connection timed out after 10000ms"
}

How It Works

The node opens a raw TCP socket to the Terazone SMTP server and performs the standard SMTP command sequence:

Client connects via TCP
Server: 220 ...
Client: EHLO mail.example.com
Server: 250 OK
Client: MAIL FROM: <[email protected]>
Server: ... Sender OK
Client: RCPT TO: <[email protected]>
Server: ...
Client: DATA
Server: ... Start mail input
Client: [MIME headers + multipart body with base64 attachment]
Client: .
Server: ... Queued mail for delivery
Client closes connection

Key details:

• No TLS — plain TCP connection
• No authentication — the Terazone relay does not require credentials
• MIME multipart — attachment sent as application/octet-stream with base64 encoding
• UTF-8 support — subject and file name are encoded using RFC 2047 Base64 (=?UTF-8?B?...?=) for Hebrew and other non-ASCII characters
• Timeout — configurable, defaults to 10 seconds

Troubleshooting

| Issue | Solution | |---|---| | Node doesn't appear in n8n | Restart n8n after manual installation. For npm install via UI, it should appear immediately. | | SMTP connection timed out | Verify network connectivity from the n8n server to the SMTP host:port. Check firewalls. | | SMTP connection error: ECONNREFUSED | SMTP server is down or port is blocked by a firewall. | | Garbled subject or filename | This is typically a mail client display issue. The node uses standard RFC 2047 Base64 UTF-8 encoding. | | Continue On Fail shows error JSON | This is expected behavior — the node catches the error and outputs it as data instead of stopping the workflow. |

Compatibility

• n8n: >= 1.0.0
• Node.js: >= 18
• Runtime dependencies: None (uses only Node.js built-in modules net and readline)

License

MIT