Email is the main communication channel for most businesses. Securing your email server is very important to secure your data and your email domain and prevent unauthorized people from accessing your data.

This article includes some of the best practices to secure your organization’s email server. Securing your email server includes the following.

  • Protecting your servers using antivirus software
  • Using email filters to filter unwanted spammy emails
  • Preventing third parties from using your organization’s domain to send emails
  • Securing emails while in transit and the ones in the inboxes of employees
  • Being aware of the steps your organization’s email service provider takes to secure email servers

Just like the importance you give to securing your website, you must also prioritize securing your email server. No matter whether you are an organization or an individual, you will need to secure your mailing list and protect your reputation. That is because hackers can easily ruin your reputation by sending spammy emails when they happen to get their hands on your mailing list. This could put you in trouble and your business will eventually lose its reputation. When many users receive such spammy emails, they are likely to raise complaints against your business, which would most likely result in your IP address and domain landing on the blocklist.

Apart from that, when hackers get their hands on important emails your business or your employees send, they could steal and misuse sensitive information in those emails. To prevent yourself from falling into such unfortunate situations, you will need to know how to secure your email server.

The following are the top tips for securing your email server.

1. Get an SSL Certificate

SSL certificates are not just for securing websites, but you can use these certificates to encrypt your email server, as well. You can secure your email server with an SSL certificate to encrypt emails in transit and authenticate the sender’s authenticity. This way, you can be assured that no third party can read your emails.

2. S/MIME Certificates

Secure/Multipurpose Internet Mail Extensions, commonly known as S/MIME certificates, are email signing certificates that function more like SSL certificates. These certificates can sign emails in transit and the ones in the inbox, as well. As all emails will be signed individually, you need not worry about cybercriminals impersonating you.

3. Firewall

Similar to network firewalls, email server firewalls screen inbound and outbound email traffic based on the rules set by your email server. They work more like spam filters and will alert you about suspicious activities. They will also deny email traffic based on the rules you have set. Firewalls will prevent your email server from becoming a victim of DDoS attacks, spam, and viruses.

4. Domain-based Message Authentication, Reporting, and Conformance

The DMARC protocol or Domain-based Message Authentication, Reporting, and Conformance protocol verify the authenticity of an email. It helps prevent cybercriminals from sending phishing emails impersonating to be you to email IDs on your mailing list. This protocol detects and prevents email-based attacks like phishing, business email compromise, spoofing, etc. By using two other protocols, Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM), it assures users that the email is from an authentic source and that it has not been tampered with in transit.

5. Update Your Server Software and Firmware

You can secure your email server by keeping your server software and firmware updated. Failing to update your server software to the current version with patches and updates could lead to issues as cybercriminals can easily exploit vulnerabilities and gain access to your email server. Software updates will include patches that will fix issues and bugs in the older version of the software that is most likely to make your server vulnerable to attacks. When you apply the patches at regular intervals and update your software whenever there is an update, you can prevent hackers and other cybercriminals from exploiting vulnerabilities and accessing your email server.


You can use Domain Name System Blacklist (DNSBL), also known as Real-time Blackhole List, to check and reject emails from IP addresses that send spammy emails. This service will check for emails from spammy IP addresses and block them. Likewise, it will block emails that contain malicious links.

7. User Security and Best Practices

Human error and brute force attacks are two ways through which cyber criminals easily gain access to email servers. It is important for organizations to make employees aware of common email threats and teach them how to prevent themselves from falling prey to attacks. It is a good practice to implement multi-factor authentication for employees who use the email server. It is mandatory to avoid keeping default usernames and passwords that hackers can easily guess. Instead, organizations must make sure they have strong, unguessable passwords.


Securing your email server is as important as securing your website. Failing to keep your email servers secure could lead to losing your reputation, as cybercriminals can easily hack your email server and carry out attacks. Hackers can easily steal your data when they gain access to your business emails. Securing your email server is the only way to protect your business, its data, and your overall reputation.


Welcome to Savvy Security, a blog focused on providing practical cybersecurity advice for website owners and small businesses. Our team brings you the latest news, best practices and tips you can use to protect your business...without a multi-million dollar budget or 24/7 security teams.