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Thu Kha Kyawe
Thu Kha Kyawe

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14.Linux Postfix Mail Server

#aws #linuxlevel2

Lab Information

xFusionCorp Industries has planned to set up a common email server in Stork DC. After several meetings and recommendations they have decided to use postfix as their mail transfer agent and dovecot as an IMAP/POP3 server. We would like you to perform the following steps:

  1. Install and configure postfix on Stork DC mail server.

  2. Create an email account anita@stratos.xfusioncorp.com identified by LQfKeWWxWD.

  3. Set its mail directory to /home/anita/Maildir.

  4. Install and configure dovecot on the same server.

Lab Solutions

🧭 Part 1: Lab Step-by-Step Guidelines

Objective

On the Mail Server (stmail01):

Install postfix

Create email user anita

Configure mailbox location

Install and configure dovecot

Server details:

Server User
stmail01 groot

1️⃣ Login to Jump Host

ssh thor@jump_host.stratos.xfusioncorp.com
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Password:

mjolnir123

2️⃣ Connect to Mail Server

ssh groot@stmail01
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Password:

Gr00T123

3️⃣ Switch to Root

sudo -i
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4️⃣ Install Postfix

yum install -y postfix
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Start and enable it:

systemctl start postfix
systemctl enable postfix
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5️⃣ Create User anita

useradd anita

# Set password:

passwd anita

Enter:

LQfKeWWxWD
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6️⃣ Create Mail Directory

mkdir -p /home/anita/Maildir

# Set ownership:

chown -R anita:anita /home/anita/Maildir
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7️⃣ Configure Postfix Mailbox Location

Edit postfix configuration:

vi /etc/postfix/main.cf

Add this line at the end:

home_mailbox = Maildir/

Save:

ESC
:wq

# Restart postfix:

systemctl restart postfix
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8️⃣ Install Dovecot

yum install -y dovecot
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9️⃣ Configure Dovecot Mail Location

Edit configuration:

vi /etc/dovecot/conf.d/10-mail.conf

Find:

mail_location =

Change to:

mail_location = maildir:~/Maildir

Save and exit.
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🔟 Start and Enable Dovecot

systemctl start dovecot
systemctl enable dovecot
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1️⃣1️⃣ Verify Services

systemctl status postfix
systemctl status dovecot
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Both should show:

active (running)

🧠 Part 2: Simple Explanation (Beginner Friendly)

What this lab builds

You are setting up a basic Linux mail server.

Two main components are required:

Component Purpose
Postfix Mail transfer agent (send mail)
Dovecot Mailbox server (read mail)

How Email Flow Works

Example:

User sends mail → Postfix
Postfix stores mail → Maildir
User reads mail → Dovecot

Architecture:

Client
↓
Postfix (SMTP server)
↓
Maildir storage
↓
Dovecot (IMAP / POP3)
Why Maildir is used

Mail storage formats:

Format Description
mbox one large file
Maildir one file per email

Maildir is preferred because it is:

faster

safer

better for concurrent access

Mail directory:

/home/anita/Maildir
What home_mailbox = Maildir/ does

This tells postfix:

Store user mail inside Maildir folder

Example:

/home/anita/Maildir/new
/home/anita/Maildir/cur
/home/anita/Maildir/tmp
Why we install Dovecot

Postfix cannot read email.

It only delivers mail.

Dovecot allows users to access email using:

Protocol Port
IMAP 143
POP3 110

Resources & Next Steps
📦 Full Code Repository: KodeKloud Learning Labs
📖 More Deep Dives: Whispering Cloud Insights - Read other technical articles
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Credits
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