What is a Mailserver?
A mailserver is a family of programs that answer email automatically. These programs are also called list servers. A good mailserver will be able to filter out spam, and prevent your mailbox from being clogged. A mailserver can be installed on the main Web server, or on a separate server.
It has two programs installed: Sendmail program and POP program
1) Sendmail Program
This program allows the mailserver to process outgoing email. If an email address does not exist, the mailserver will return the mail to the sender.
If the sender sends the mail to a particular email address and if that email address does not exist then the mailserver send the mail back to the sender.
If any technical problem arises during the mail delivery, the mail might be returned back to the sender. In all cases in which mail is returned, it arrives with an explanation or error code. By reading the error code you can determine why the mail failed to reach its destination.
2) POP Program
The POP (Post Office Protocol) program collects incoming email. As it receives mail, it creates a single text file of accumulated messages for each email address. If the end-user has configured his or her email client to delete mail from the server upon collection, the mailserver’s text file is wiped when the mail is collected. Some people, however, store email on the mailserver. This is not only a privacy concern, but can also lead to malfunctions on the mailserver when text files become too lengthy.
