Part 3.2: Setup iRedMail Server on Linux in less than 20 minutes

Sun, 22 Mar 2026 14:24:59 +0530

Note

This walkthrough is part of the Cloning Gmail’s Architecture series. For better context, I suggest you to start from Part 1

In this tutorial, we will look how to configure a mail server (iRedMail) on the EC2, assign an Elastic IP (static public IP), enable port access for SMTP / IMAP communications and more, to replicate an actual email flow from server to server.

Pre-Requisites Link to heading

You have access to a linux environment where you want to configure iRedMail.
Network connection on that linux environment.
Privileges to run the commands as a super user.
A TLD domain to setup mail server’s hostname and configure settings.

Info

Make sure to replace example.com with the domain that you have registered with your DNS provider. Use of example.com is for merely demo purposes to showcase how DNS mapping is working.

Prepare the Linux Instance Link to heading

Part 1: Mail Server Communications 101

Sun, 01 Mar 2026 23:21:21 +0530

This guide explains the core building blocks required to send and receive email via the internet. It focuses on a understanding how the email is sent across the real world and what protocols are used within this communication.

The Components of a Mail Communication Link to heading

DNS Server: Routes trusted servers, handles MX / SPF / DKIM records for mail delivery and authority verification.
Mail Servers: Receives outbound emails from clients and moves messages across each other using SMTP.
Mail Client: Applications used by people to send / receive emails (eg. Outlook, Thunderbird).

Mail Server Communication Model

Mail flow Link to heading

You write an email on thunderbird and press Send.
Your mail client submits it to your mail server using SMTP (port 587).
Your mail server checks the recipient’s domain.
It queries DNS to find the domain’s MX record.
DNS tells your server which mail server handles that domain.
Your server connects to the recipient’s server using SMTP (port 25).
The recipient server verifies security (SPF/DKIM/TLS).
If valid, it accepts and stores the email.
The recipient’s mail client connects via IMAP (993) or POP3 (995).
The email appears in their inbox.

1. DNS Server Link to heading

Before email works, the internet must know which server handles mail for a particular domain, where that server is located and whether that server is trusted. This is handled through DNS (Domain Name System).

Spf on DevLogs

Part 3.2: Setup iRedMail Server on Linux in less than 20 minutes

Pre-Requisites Link to heading

Prepare the Linux Instance Link to heading

Part 1: Mail Server Communications 101

The Components of a Mail Communication Link to heading

Mail flow Link to heading

1. DNS Server Link to heading