Preventing unauthorized SMTP hosts from using Domino® as a relay

To protect SMTP servers from unauthorized relaying, Domino® provides inbound relay controls used to define the hosts to which and from which a server can relay messages. The Domino® SMTP listener denies requests to relay messages to or from unauthorized hosts

About this task

To prevent misuse of your system, configure Domino® to prevent open relaying, while allowing relays originating from and destined for known domains and hosts. By default, a new Domino® SMTP server prevents external hosts from relaying mail to any destination. You can further customize Domino's anti-relay controls to specify when relays are and are not allowed.

The Router/SMTP > Restrictions and Controls > SMTP Inbound Controls tab of the Configuration Settings document provides two sets of controls for managing relay access:

  • Inbound relay controls
  • Inbound relay enforcement

Use the Inbound relay controls to restrict relays by destination and origin. Use the relay enforcement controls to selectively apply the relay restrictions based on the originator's relation to the local Internet domain, host name, or authentication status.