documentation_complete: true

title: 'Require SMTP AUTH Before Relaying from Untrusted Clients'

description: |-
    SMTP authentication allows remote clients to relay mail safely by
    requiring them to authenticate before submitting mail. Postfix's SMTP AUTH uses
    an authentication library called SASL, which is not part of Postfix itself.  To
    enable the use of SASL authentication, see
    <weblink-macro link="http://www.postfix.org/SASL_README.html" />
