Linux Administration

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How to Setup sendmail server on red hat linux

Email Delivery Process :

  • Mail User Agent (MUA)
  1. To be able to send mail, you, or your users, need a program called a Mail User Agent (MUA). The MUA, also called a mail client, enables users to write and read mail messages.
  1. Two types of MUAs are available: a graphical user interface (GUI), such as Netscape Messenger, and a command-line interface, such as Pine.
  • Mail Transfer Agent (MTA)
  1. Whether your MUA is a GUI or command-line interface, after the message is composed, the MUA sends it to the mail transfer agent (MTA).
  1. The MTA is the program that sends the message out across the network and does its work without any intervention by the user.
  • The MTA installed by default on your Red Hat system is called Sendmail.
  1. The MTA reads the information in the To section of the e-mail message and determines the IP address of the recipient’s mail server.
  1. Then the MTA tries to open a connection to the recipient’s server through a communication port, typically port 25.
  1. If the MTA on the sending machine can establish a connection, it sends the message to the MTA on the recipient’s server using the Simple Message Transfer Protocol (SMTP).
  • Local Delivery Agent (LDA)
  1. After the LDA receives the message from the MTA, it places the message in the receiver’s mailbox file that is identified by the username.
  1. On your Red Hat system this is a program called procmail. The location of the user’s mailbox file is
    /usr/ spool/mail/<user’s name>.
  • The final step in the process happens when the user who is the intended receiver of the message reads the message. The user does this using the MUA on his or her PC.
  • Mail Notifier
  • An optional program is a mail notifier that periodically checks your mailbox file for new mail. If you have such a program installed, it notifies you of the new mail.
  • If new mail has arrived, the shell displays a message just before it displays the next system prompt. It won’t interrupt a program you’re running.
  • You can adjust how frequently the mail notifier checks and even which mailbox files to watch.
  • If you are using a GUI, there are mail notifiers available that play sounds or display pictures to let you know that new mail has arrived.
  • Configuring Sendmail:




Now send mail from user kiranmail to clientmail

Command is:


Posted By-: Vissicomp Technology Pvt. Ltd.

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