Mail Services details with postfix example

SMTP -for using outgoing mail server

POP&IMAP - for using incoming mail server from mail reception

MUA - mail client agent - outlook, thunderbird, etc..

MTA - mail transfer agent  which will sends the message to the remote MTA

MDC - mail delivery agent, will will delivers the message to the recipient mailbox

Relaying - mails are sent to an outgoing mail server for further processing

Postfix is one of the relaying mail server. sent mail for central mail server for further processing.

we need one server and client for performing this

server

#systemctl enable postfix

#firewall-cmd --permanent --add-service=smtp

#firewall-cmd --reload

#vi /etc/postfix/main.cf

inet_interfaces = all
#inet_interfaces = localhost
inet_protocols = ipv4

myorigin = $mydomain

#mydestination = $myhostname,localhost,$mydomain,localhost

//make the changes as appears above and save them

#systemctl restart postfix

#postfix check
//if you have any error it will list here

client

#vi /etc/postfix/main.cf

inet_interfaces = loopback-only
inet_protocols = ipv4

myorigin = $mydomain

mynetworks = 127.0.0.1/8

relayhost = 192.168.1.10  //server address , mail server address.

//save and restart

#tail /var/log/mail/log ///for check the log

#mail -s "testmail" root@mail.boobi.com <

// that's it the mail has been sent

//we can send mail to email address which the domain

#echo "test mail" | mail -v -s " test mail" boobalan@companydomain.com

Or

#mailx -vvv boobalan@companydomain.com
Sub : test


EOT

#mailq

//this will help to show the mails

#mail