The question of bounce emails has been going through my mind of late. I had been trying to figure out a link which helps me understand in simple words the answer to my question. After a lot of keyword rephrasing and sifting over internet links I found this useful link which I want to share with those who are interested. Particularly the first four paragraphs are useful and give you a basic understanding. Some of the critical things one should look for when establishing a mail server is have a POP server (receives bounced emails), automatically filtering out which emails are hard bounced or soft bounced and then remove them from the database.