Released Postfix 3.1.0 With few fixs

Postfix is free, open-source, fast and popular, SMTP mail transfer agent (MTA) which is using widely as alternative for Sendmail. Postfix implements a high-performance parallelized mail-delivery engine. Postfix is often combined with mailing-list software (such as Mailman). Postfix can run on UNIX-like systems including AIX, BSD, HP-UX, Linux, MacOS X, Solaris, and more. The latest version of Postfix 3.1.0 released on February 24, 2016 with few fixs.

1) Install Postfix

All the modern Linux distribution by default having postfix binary package on their own repository, so we can easily install by issuing below single command. By default Sendmail installed most distribution so remove it before processing postfix installation.

[Remove sendmail, if its not installed you can skip]
# yum remove sendmail

[Install Postfix]
# yum install postfix 

Add hostname entry into /etc/hosts file, so that it will discover the hostname when you are testing the postfix
configuration.

# nano /etc/hosts
192.168.0.100 centos.2daygeek.com

2) Configure Postfix

Edit the /etc/postfix/main.cf file, uncomment below lines and make necessary change as per your domain, mail server details, networks & reset of the things are same.

# nano /etc/postfix/main.cf
myhostname = centos.2daygeek.com
mydomain = 2daygeek.com
myorigin = $mydomain
inet_interfaces = all
inet_protocols = all
mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
mynetworks = 127.0.0.0/8
relay_domains = $mydestination
home_mailbox = Maildir/

3) Restart Postfix

Once you have done appropriate above changes, just fire the below commands to restart postfix service to take effect the changes on new configuration.

[For SysVinit Systems]
# service postfix restart
# chkconfig postfix on

[For systemd Systems]
# systemctl restart postfix
# systemctl enable postfix

4) Open Firewall Port

You have successfully installed & configured postfix mail server and you need to allow from firewall to work properly.

[For CentOS/RHEL 5 & 6, Fedora old systems]
# iptables -A INPUT -m state --state NEW -m tcp -p tcp --dport 25 -j ACCEPT 
# iptables -A INPUT -m state --state NEW -m udp -p udp --dport 25 -j ACCEPT 

[For CentOS/RHEL 7, Fedora new systems]
# firewall-cmd --permanent --add-service=smtp
#  firewall-cmd --reload

5) Test Postfix

Now you are ready to test your postfix mail service whether its working fine or not, use the below tricks.

# telnet localhost smtp
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 centos.2daygeek.com ESMTP Postfix
ehlo localhost
250-centos.2daygeek.com
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
quit
221 2.0.0 Bye
Connection closed by foreign host.

6) Test Postfix with User

Create user with /sbin/nologin shell to restrict login access.

# useradd -m magi -s /sbin/nologin
# passwd magi
# telnet localhost smtp
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
220 centos.2daygeek.com ESMTP Postfix
ehlo localhost
250-centos.2daygeek.com
250-PIPELINING
250-SIZE 10240000
250-VRFY
250-ETRN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250 DSN
mail from: [email protected]
250 2.1.0 Ok
rcpt to: [email protected]
250 2.1.5 Ok
data
354 End data with .
This is test mail
.
250 2.0.0 Ok: queued as B3520209D919
quit
221 2.0.0 Bye
Connection closed by foreign host.

See the below output.

# cat /home/magi/Maildir/new/1456287731.Vfd00I159298M878550.centos.2daygeek.com
Return-Path: 
X-Original-To: magi
Delivered-To: [email protected]
Received: from centos.2daygeek.com (centos.2daygeek.com [IPv6:fe80::a00:27ff:fe76:2100])
    by centos.2daygeek.com (Postfix) with ESMTP id A857E209D919
    for ; Wed, 24 Feb 2016 09:51:42 +0530 (IST)
Message-Id: <[email protected]>
Date: Wed, 24 Feb 2016 09:51:42 +0530 (IST)
From: [email protected]

This is test mail

Enjoy…)