documentation_complete: true

title: 'Control Mail Relaying'

description: |-
    Postfix's mail relay controls are implemented with the help of the
    smtpd recipient restrictions option, which controls the restrictions placed on
    the SMTP dialogue once the sender and recipient envelope addresses are known.
    The guidance in the following sections should be applied to all systems. If
    there are systems which must be allowed to relay mail, but which cannot be
    trusted to relay unconditionally, configure SMTP AUTH with SSL support.
