How to Setup Postfix on CentOS 6.4

Postfix is a open-source mail transfer agent (MTA) that routes and delivers electronic mail. Postfix is an alternative for Sendmail service which provide the same function. This post will describe on how you can install and setup postfix on CentOS 6.4. After you installed postfix, you can use postfix command to controls the operation of the Postfix mail system such as start or stop the master daemon, do a health check, and other maintenance.

1. To install Postfix, use the following yum command :

[root@centos64 ~]# yum install postfix -y

2. To verify if Postfix is already installed, use the following rpm command :

[root@centos64 ~]# rpm -q postfix

Example :

[root@centos64 ~]# rpm -q postfix
postfix-2.6.6-2.2.el6_1.x86_64

3. How to check Postfix version :

[root@centos64 ~]# postconf -d | grep mail_version

Example :

[root@centos64 ~]# postconf -d | grep mail_version
mail_version = 2.6.6
milter_macro_v = $mail_name $mail_version

4. Configure Basic postfix main.cf file :

[root@centos64 ~]# vi /etc/postfix/main.cf

Uncomment and modify the following two line :

myhostname = centos6.4.ehowstuff.local
mydomain = ehowstuff.local

myhostname: is the host name of the system (i.e, the system is called mail or mail.example.com).
mydomain: is the domain name for the email server (it can be a real or fake domain name).

5. Start the postfix service :

[root@centos64 ~]# service postfix start
Starting postfix:                                          [  OK  ]

6. Restart the postfix service :

[root@centos64 ~]# service postfix restart
Shutting down postfix:                                     [  OK  ]
Starting postfix:                                          [  OK  ]

7. How to show postfix pid number on running for postfix services ?

[root@centos64 ~]# ps -ef | grep postfix
root      3081     1  0 05:57 ?        00:00:00 /usr/libexec/postfix/master
postfix   3083  3081  0 05:57 ?        00:00:00 pickup -l -t fifo -u
postfix   3084  3081  0 05:57 ?        00:00:00 qmgr -l -t fifo -u
root      3292  1963  0 06:40 pts/0    00:00:00 grep postfix