I am running;

Red Hat Linux release 7.1

Currently i have SMTP outgoing mail server disabled. Pls advice how i can enable the smtp Mail-Auth so that only authenticated users can relay mails though my server and no one else can.

Also, pls let me know how do i disable the SMTP_AUTH and stop mail relay when i want to.

Also, MOST IMPORTANTLY, i hear the SMTP_AUTH is an ALL or NONE feature, is there anyway i can configure Sendmail to allow only selected users hosted on my server to be able to relay mails while the others cannot.

Thanks in advace for your responses.