SMTP Concentrator

Customers often use a hybrid email setup that combines cloud, on-premise, and legacy applications. Most legacy applications cannot establish secure connections over the internet or support authentication.

The Retarus SMTP Concentrator (hereafter referred to as the App) acts as a secure and reliable email proxy. It creates TLS-encrypted SMTP sessions between applications in the customer’s data center and the Retarus Transactional Email Services API. As a bridge, the App enables customer systems to send email messages securely through the Retarus infrastructure without exposing them directly to the public Internet.

The App lets customers manage client credentials so their applications can authenticate securely with the App. After authentication, the App uses its own credentials (provided by Retarus) to connect to the Retarus Transactional Email Services API and relay messages in an encrypted form.

The App simply forwards emails within each client session and does not queue messages or store them.