Postfix/main.cf/smtp sasl auth enable

page type::listing page type::subpage thing type::config parameter
 * parameter: name::smtp_sasl_auth_enable
 * default: unknown
 * versions: unknown
 * values: no|yes
 * purpose: summary::enables authentication from local SMTP client to external SMTP relay server

About
This parameter must be set to yes in order to for the Postfix SMTP client to authenticate with an external SMTP server (as specified in ) to relay messages.

If it is set to no, it essentially disables the parameter.