SMTP Server Monitor

The SMTP monitor in updu tests connections to an email server. It establishes a TCP connection to the host and port and verifies that the server responds with a standard SMTP 220 greeting indicating it is ready.

Configuration Options

When setting up an SMTP monitor, you can configure the following options:

Basic Settings

• Name: A descriptive name for your monitor.
• Group: Optional group assignment for organizing monitors.
• Interval (seconds): How frequently updu should perform the check.
• Timeout (seconds): The maximum time updu will wait for a response before considering the check failed.

SMTP Specific Settings

• Hostname: The IP address or domain name of the email server (e.g., smtp.gmail.com).
• Port: The port the email server is listening on. Standard ports are 25 (unencrypted), 465 (SMTPS), or 587 (STARTTLS).
• Require TLS: (Optional) Check this box if the server requires an initial TLS handshake (e.g., port 465). This determines how updu builds the initial connection.

Example Use Cases

• Mail Relay Availability: Monitor your self-hosted Postfix or external email gateway to catch hangs and firewall drops that would otherwise silently break delivery.