Skip to content

SMTP configuration

What is it?

The SMTP configuration page (Settings > Security > SMTP configuration) lets platform administrators configure outbound email sending directly from the OpenCTI interface — without editing backend configuration files or restarting the platform.

Why use it?

Configuring SMTP from the interface has several advantages:

  • Changes take effect immediately, without a deployment restart.
  • Credentials are encrypted and stored securely in the database.
  • Supports both Basic and OAuth2 authentication.

The interface configuration takes priority over the backend JSON/environment-variable configuration when the Use configuration in interface toggle is enabled.

Page states

The page has three possible states depending on the platform configuration.

Interface configuration disabled by the administrator

When the smtp:forced_sender_email backend parameter is set, the platform administrator has locked the SMTP sender address at the infrastructure level. In this case:

  • The configuration table is displayed in read-only (greyed out).
  • The Update button is not available.
  • A warning message is displayed: Your platform administrator has disabled this feature. You cannot configure a new SMTP configuration within the interface.

To re-enable interface configuration, remove smtp:forced_sender_email from the backend configuration and restart the platform.

Interface configuration not yet activated (Use configuration in interface disabled)

When smtp:forced_sender_email is not set but the Use configuration in interface toggle is disabled, the platform is using the backend JSON/env configuration. In this case:

  • An info message is displayed: Currently, the SMTP is configured via a backend configuration. To change your configuration, simply enable the usage of the Interface configuration & define your SMTP configuration in this screen.
  • The Update button is available. Open it to enable the toggle and fill in your SMTP settings.

Interface configuration active (Use configuration in interface enabled)

When the interface configuration is active, the table displays all current SMTP settings and the following buttons are available:

  • Update — open the configuration drawer to edit the settings.
  • Test — send a test email to verify the configuration.

Configuration fields

Field Description
SMTP enabled Globally enables or disables outbound email sending
Use configuration in interface When enabled, the interface configuration overrides the backend config
Sender email address The From: address used for all outbound emails
Hostname SMTP server hostname
Port SMTP server port
Use SSL/TLS Enable SSL/TLS encryption
Reject unauthorized certificates Reject connections with invalid TLS certificates
Authentication type basic (username/password) or oauth2
Username SMTP username — Basic auth only
Password SMTP password — Basic auth only (stored encrypted)
OAuth user Email address of the SMTP mailbox — OAuth2 only
OAuth client ID OAuth2 client ID
OAuth issuer OIDC issuer URL used for token discovery and refresh
Refresh token expiration date Expiry date of the OAuth2 refresh token

Port 25 is blocked

Port 25 is not allowed in the interface configuration. Use port 465 (SSL/TLS) or 587 (STARTTLS) instead.

OAuth2 authentication

The OAuth2 flow uses the Refresh Token Grant. OpenCTI automatically refreshes the access token before each email is sent. Refer to SMTP Service configuration for provider-specific notes (Microsoft 365, Google Workspace, etc.).

What's next?