Linux Mail Server Setup and Howto Guide

Hi Consultant,

           I am facing a problem in my mailserver, from one domain i am rarely getting mail delivered . For most of the time, when i see in log file it shows hold received from and to user it showing then it should proceed with mailscanner but that is not recorded in the log. the status of the mail could not found in the log and message header is no where placed in the server.

         Secondly, how to whitelist the entire domain to get emails from that domain.

                Thanks in advance