How SSL Secure Your Mail Server?

Everything You Need to Know About SSL Mail Server Certificates to Secure Your Email Server

Email security is pioneer security in today’s world. Small and medium-sized businesses face vulnerabilities when they do not pay attention to email security. To protect client accounts and their details, proper email security measures should be adopted. Email access and its control, encrypted email, web application firewall, spam filtering are few measures that an organization could take to make email security better.

How Website Security and Email Security are Kind of Similar?

Website security and email security are different. Website security secures the data transition between the server and the browser while email security prevents unauthorized access to email accounts, email content, and email communication. Emails are entry points to access the organization’s network and take control of data. Email encryption encodes the email and protects the important information by making sure that the intended recipient only can read the message.

Website security on other hand creates a secure tunnel in which sensitive information travels from one end to another end (browser and server). A third party cannot sniff ongoing information due to strong encryption.

Why Email Security Is a Must These Days?

Rising attacks have made email security compulsory nowadays. Employees transfer sensitive information via email in their daily routine and such information should have better protection. A research report of 2019 says that 16% of employees believed that due to lack of email security, there was data loss in organizations. While 82% of organizations believed that they have faced an email-based attack in the past year. The below image shows the impact of email security attacks on companies.

An organization should have proper infrastructure and well-designed policies that stop unauthorized access to email accounts and email communication. Email security, by the way, offers encryption, spamming, spyware protection, security for login. Phishers always try to lure users to click on malicious links and software. Once a hacker gets access to an organization’s network, there are high chances of network infiltration. To avoid such incidents, email security is important. For better results, an organization should give proper training and educate employees. Many companies adopting different emails security options that can be seen in the below image.

Why You Should Use an SSL/TLS Certificate for Your Mail Server?

SSL/TLS certificate encrypts the ongoing email communication and verifies that the email server is the one with whom you intended to communicate with. If there is the absence of an SSL certificate, the information will flow between the server and a user remains in plain text. An attacker could imitate the server and extract the email details during the process. Moreover, the possibility of a Man-in-the-middle attack cannot be ignored where an attacker can tamper with email data and perform a data breach in a company. With an SSL certificate, you can log in mail server securely and the login credential will travel to the server in encoded form instead of a plain text.

There is S/MIME (Secure/Multipurpose Internet Mail Extensions) certificate for email security that provides email authenticity, email integrity, and email privacy. S/MIME is a type of end-to-end encryption solution and signs email messages to authenticate the sender’s identity. You can send and received an encoded email. S/MIME uses a public key to encrypt the message and it can only be a recipient who has a private key. Many antiviruses due to encryption of email content cannot detect the URLs in emails or malicious software downloads. In this case, it is hard to stop an email-based attack where a legitimate user’s account is used.

Types of Certificates That Work for Microsoft Communications Servers

As discussed, SSL certificates also work for email security and we here give a glimpse on types of SSL certificates used to secure Microsoft Communication Servers. The certificates are ideal to secure Microsoft Exchange servers 2007,2010, 2013, 2016. These SSL certificates also secure Microsoft services like mail, webmail, outlook, Autodiscover, office communication server. Such an SSL certificate is called a UCC SSL certificate (Unified Communication certificate). Depend on the number of domains, the UCC certificate can be multi-domains and multi wildcard domains. The below image shows SSL certificates offered by that helps to secure MS communication servers.

Comodo UCC / Exchange SSL

Comodo PositiveSSL Multi-Domain Wildcard

GeoTrust Multi-Domain SSL (UCC)

Our Cheapest Price $63.92/yr. $90.00/yr. $251.43/yr.
Buy Now Buy Now Buy Now
CA Price $273.60/yr. $383.04/yr. $347.03/yr.
Secure Multiple Domains Multiple Domains & Its All Subdomains Multiple Domains
Validation Type Domain Domain Organization
Issuance Time 10 Minutes 10 Minutes 1-3 Days
SSL Encryption 256-bit 256-bit 256-bit
Key Encryption 2048 bits 2048 bits 2048 bits
Server Licenses Unlimited Unlimited Unlimited
Google Rankings Boost Yes Yes Yes
WebTrust Seal Yes Yes Yes
Reissue Policy Yes Yes Yes
EV Support No No No
Wildcard Support No Yes No
SAN / UCC Support Yes Yes Yes
Browser Support 99% 99% 99%
OS Support Yes Yes Yes
Smartphone Support Yes Yes Yes
Warranty By CA USD $250,000 USD $10,000 USD $1,250,000
Refund Policy 30 days 30 days 30 days
Free Reissuance Yes Yes Yes
Support Yes Yes Yes
Buy Now Buy Now Buy Now

Types Of Email Threats:

  • Eavesdropping: with eavesdropping person can recognize other’s mail path and can read the person’s message without his awareness. There are many activities going over the internet where people steal information about users and use it in a counterfeit way. It is like to hear someone’s phone conversation sitting in a nearby room.
  • Identity Theft: If someone has information like username and password, he can read a message and can misuse it. They can send false mails to you using login details. Such credentials can be found by eavesdropping on SMTP, POP, IMAP, or Webmail connections.
  • Modification: A person is having administrator rights or SMTP server permission can read and modify a message. Before reaching the destination such person can delete or change a message. Therefore, the recipient will never know about such modified or deleted messages.
  • False Message: After taking the hold on email server hackers can send false messages to the recipient. Sometime they reply to sender with faked message that appear to be valid. In that as soon as sender opens such message he becomes victim of online attacks because of malicious links.
  • Secure Email with SSL: From the above threats, it is now understood that how much email is secure over the internet? To avoid such vulnerability and threats there is a niche solution for email security called SSL (secure socket layer) protocol that secures email with robust encryption so that no one can interrupt them. SSL works on symmetric and asymmetric key.

Benefits Of SSL:

There are benefits in using SSL protocol for the mail server.

  • A person can send encrypted messages to his receiver without interruption.
  • A person can prove that he received a message from a reliable server.
  • Digitally Signed messages are highly authenticated because a person will find his digital signature in a particular message. Such digital signature should be added first before encoding a message.
  • The communication will remain safe and secure with SSL protocol.
  • The privacy aspect will be maintained with SSL protocol.

Symmetric key means the sender and receiver use a secret key to encrypt and decrypt the message. However, symmetric key has some problems because if a person does not recognize or meet the other person he cannot correspond with him.

On contrary Asymmetric key, which is known as a public key, each individual has two keys like private and public key. If a person encrypts a message with the private key can only be decrypted with the public key. The public key is given out to anyone who needs a copy of the message but the private key should be kept secret.

Below mentioned is the process when a person connects to the server enabled with SSL.

  • First, the server connects to the server using a private key to prove that a person is connecting to a legitimate server and not the middleman, which can steal the information.
  • A session sends the public key to the server.
  • Now server gives a secret key and encrypt it with a person’s public key.
  • Now both of person and the server communicate with symmetric key encryption with this shared secret key.


Scenario 1:

Need to secure a single hostname for mail server like Linux and Apache based mail servers are commonly setup with single hostname only.

Recommended Product: Purchase Thawte SSL123 Certificate to secure single hostname.

Product Validation Issuance Offer Price CA Price
Thawte SSL123 Domain 10 minutes $33.93/yr. $144.03/yr.

Scenario 2:

Widely used mail servers like Microsoft Exchange (2003/2007/2010) default configuration creates multiple hostname like,,

In this case SAN/UC certificates are recommended by Microsoft. We recommend Comodo UCC SSL certificate for exchange server.

Product Validation Issuance Offer Price CA Price
Comodo UCC / Exchange SSL Domain 10 minutes $63.92 /yr. $273.60 /yr.

Scenario 3:

You can use Wildcard SSL certificates for exchange server that will be issued for * We recommend RapidSSL Wildcard certificate if you choose Wildcard SSL certificate for exchange.

Product Validation Issuance Offer Price CA Price
RapidSSL Wildcard SSL Domain 10 minutes $100.80/yr. $192.37/yr.


Email is a necessity in any business world and there are many mail transitions taking place every day. In that case, a business mail server must have such security that can prevent eavesdropping, identity theft in case of email. We have observed about how SSL can secure email with strong encryption. Many certificate authorities provide legitimate secure connection for Web-mail, POP, IMAP, and SMTP servers.

Strong recommended to pass mail server security check and hire professional services and also test server security with trusted third party tools. Always hire certified administration to setup business mail server.

Not sure what to do?

  • Try Google Apps for mail service. Earlier Google Apps for mail service was free cost, but now it’s paid service.
  • Try Microsoft OFFICE 365. Highly trusted and reliable hosted mail service. Obviously its user friendly as outlook desktop application.

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