Exim Mail Server Configuration in CentOS 7 - A Comprehensive Guide

Nov 13, 2023

Welcome to First2Host, your go-to source for expert IT services, computer repair, internet service providers, and web design solutions. In this detailed guide, we will walk you through the process of configuring your Exim mail server in CentOS 7, ensuring efficient email management for your business.

Understanding Exim Mail Server

Exim is a widely-used mail transfer agent (MTA) that handles email delivery on Linux systems. It offers advanced features, robust security, and exceptional reliability, making it a popular choice for businesses of all sizes.

If you're running CentOS 7, configuring Exim as your mail server can be done quickly and effortlessly. Let's dive into the step-by-step process:

Step 1: Installing Exim Mail Server

To begin, make sure you have root access to your CentOS 7 server. Open a terminal or SSH into your machine and follow these instructions:

  1. Update your system's package repository by running the command sudo yum update.
  2. Install Exim by running sudo yum install exim.
  3. Once the installation is complete, start the Exim service using the command sudo systemctl start exim.
  4. Configure Exim to start on system boot with sudo systemctl enable exim.

Congratulations! You have successfully installed Exim mail server on your CentOS 7 machine. Now, let's move on to the next step of the configuration process.

Step 2: Configuring Exim for Sending and Receiving Emails

Before Exim can handle incoming and outgoing emails, we need to configure it properly. Follow these steps to set up Exim for email delivery:

  1. Navigate to the Exim configuration directory by running cd /etc/exim.
  2. Edit the main configuration file using your preferred text editor. We recommend using vi or nano for this task. Run sudo vi exim.conf or sudo nano exim.conf.
  3. Inside the configuration file, locate the sections related to sending and receiving emails. This includes options like smtp_transport, local_domains, domainlist local_domains, and more.
  4. Update the settings according to your specific requirements. Ensure that you provide accurate information such as domains, IP addresses, and relay configurations.
  5. Save the configuration file and exit the editor.
  6. Restart the Exim service for the changes to take effect. Use the command sudo systemctl restart exim.

Perfect! Your Exim mail server is now ready to send and receive emails. Let's move on to additional configurations to enhance its performance and security.

Step 3: Advanced Exim Configuration

While your Exim mail server is functional after the basic configuration, you may want to optimize it further for better performance and security. Here are some recommended techniques:

SPF and DKIM Authentication Setup

Implementing Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) authentication can significantly improve the deliverability of your emails. This prevents your messages from being flagged as spam or phishing attempts.

To set up SPF and DKIM, follow these steps:

  1. Generate an SPF record for your domain using the SPF Wizard provided by First2Host.
  2. Create a DKIM key pair using a tool like OpenDKIM or First2Host DKIM Generator.
  3. Add the generated SPF record and DKIM key to your DNS zone configuration. Contact your DNS provider for specific instructions.
  4. Update your Exim configuration to include SPF and DKIM checks for incoming emails. This helps validate the authenticity of received messages.
  5. Restart Exim to apply the changes.

Implementing SSL/TLS Certificates

Securing email transmissions using SSL/TLS encryption is crucial to protect sensitive information. To configure SSL/TLS certificates on your Exim mail server:

  1. Obtain an SSL/TLS certificate from a trusted certificate authority (CA) like Let's Encrypt, Comodo, or VeriSign.
  2. Install the certificate on your server and ensure the appropriate permissions are set.
  3. Update your Exim configuration file to enable SSL/TLS encryption for incoming and outgoing connections.
  4. Restart Exim to activate SSL/TLS encryption.

By implementing SPF, DKIM, and SSL/TLS certificates, your Exim mail server will achieve a higher level of security and trustworthiness.


Congratulations! You have successfully configured your Exim mail server in CentOS 7. With our comprehensive guide, you can ensure efficient email management for your business. Remember, a well-configured mail server is essential for reliable communication and successful email delivery.

At First2Host, we specialize in IT services, computer repair, internet service providers, and web design. Whether you need assistance with Exim mail server configuration or other technical solutions, our team of experts is ready to help.

For more information about our services, please visit our website at www.first2host.co.uk. Contact us today to unlock the true potential of your business!

exim mail server configuration in centos 7