Electronic mail or e-mail is an important part of your professional business communication. For your personal use or if you're a home - business web-based email service could suffice, however if you are running large-scale business, such as an online shop, a dedicated mail server will be needed.

There are many benefits when you set up an SMTP server on a Linux server. These are only a few of the many benefits that a Linux mail server can provide:

Secure, reliable, and expandable.
Does not require costly hardware.
Supports POP3, IMAP and web mail access.
It is possible to install a strong anti-spam filter and an effective antivirus to make your computer Get More Info secure.

There are a variety of ways to configure the server to run it according to your needs. Postfix is one of the most simple open-source mail transfer agent (MTAs) I've come across. It's also highly reliable. It can be deployed in one-user and multi-user equally easily. It is extremely versatile and is a great fit in every environment.

Step-by-step instructions to set up a mailserver in CentOS 7
Before you start, make sure that you update your system and install Epel Release in your server.

# yum update - y.

yum Install Epel-release

Installation
These steps will allow you to set up Postfix mail server easily:

1.) Type the following command to install postfix packages:

yum install postfix - the y

This is it! The installation will spontaneously start the Postfix daemon for you. You are able to test it after the installation has been completed.

# telnet localhost 25

It will show an image on the screen, such as:

Try ::1...
Connected to localhost
Escape character '^]'.
220-mail.znettest.tk ESMTP Exim 4.89_1 #1 Tue, 20 Feb 2018 13:29:17 +0530
220-We do not authorize the use of this system to send unwanted,
220 and/or bulk email

Note: Here, mail.znettest.tk is the hostname of this server.

Configuring SMTP server on Linux
Configuring Postfix

The Postfix mail server has one important configuration file /etc/postfix/main.cf in which all the information are stored for the mail server.

Open the file in the vi or any other text editor, and search for the next section:

vi /etc/postfix/main.cf

Myhostname=
inet_interfaces= all
inet_protocols= ipv4
alias_maps = hash: /etc/aliases
mydestination =
mynetworks =

These are the parts of the configuration file you should focus on. There's not much to do, I have to say. Underneath are the sections you'll need to set up:

Myhostname: This parameter indicates the hostname of the Internet for this mail daemon. It is recommended to use the fully-qualified domain name.

mydestination: This parameter specifies the destinations that this machine will provide locally. Make use of the local configuration that was defaulted in the server . Change the localhost to the domain name.

mynetworks: This option is slightly riskier. This entry will identify authorized destinations that mail can be transmitted from. There is a chance that your subnet will be successfully added.

Mynetworks has an entry which looks like this:

mynetworks = 127.0.0.1/8

The entry above is a safe entry and refers to local machines only.

Inet_interfaces defines the address of the network interface from which it will receive mail. By default, the program ensures all active interfaces on the machine. This parameter regulates the delivery of mail to user@[ip.address[ip.address].

inet_protocols= IPv4

It defaults to IPv4 to speed up delivery of mail

Now, save and close the vi editor. After that, you can start/activate the mail service with the command so that it becomes Active after server reboot.

systemctl restart postfix

# systemctl enable postfix

The installation of the mail service is complete. Now it is time to create an account and test it.

Create users

This is an Linux mail server. You should ensure that your username matches your email addresses. This command can be used to create user accounts:

useradd useradd USERNAME (USERNAME is the actual name of the user).

Next, you will need to enter your username and password.

passwd USERNAME

Testing Your Server

You can use mail utils package to install the things needed to send out mail by using the command:

Yum install mail with x-y

After this Try any mail ID by entering:

Mail (mailid).

It will ask you to enter the subject. Please enter the content that you wish to send.

After you've finished, exit the mail and close it with the dot (".")

Your mail server is now in good condition to send out mails in accordance with your needs.

You can also use SMTP relays to enable multifunction devices, printers or an application for sending emails making use of Office 365 and Exchange Online. And with ZNetLive You can select from different Microsoft Office 365 plans as per your needs to allow you to manage your business with ease in any location and at any time.