What Is A Mail Server?

Date First Published: 25th March 2024

Topic: Computer Networking

Subtopic: Network Services

Article Type: Computer Terms & Definitions

Difficulty: Medium

Difficulty Level: 5/10

CONTENTS

Types Of Mail Servers
How Do Mail Servers Work?
Difference Between A Mail Server and A Mail Client
Security Features

Learn about what a mail server is in this article.

A mail server, also known as an email server, is a computer system that handles and delivers emails over a network. Mail servers contain mail server software to function, which enables the system administrator to create and manage email accounts for any domain names hosted on the server. Without mail servers, users would have no way of transferring emails from one client to another.

Types Of Mail Servers

There are two main types of mail servers. These include:

Incoming mail server - Stores mail and sends it to a user's inbox. IMAP and POP3 protocols receive email messages and are used to process incoming mail.
Outgoing mail server - Operates by having a user's computer communicate with SMTP, which handles outgoing mail requests.

How Do Mail Servers Work?

When sending an email, the outgoing mail server uses an outgoing mail protocol, such as SMTP, to check the sender's email data and determine where the message needs to be sent. This is done by using DNS to translate the recipient's domain name into an IP address. It then locates a mail delivery agent by querying mail exchange (MX) records, which tell the server how to route the message to its final destination.

Once the MX record returns the appropriate destination, the incoming mail server uses an incoming mail protocol, like IMAP or POP3 to retrieve the email message from the mail server and deliver it to the specified mail client(s).

Difference Between A Mail Server and A Mail Client

The main difference between a mail server and a mail client is that a mail server is a computer that uses email protocols to move messages between email clients, whilst an email client is an application that allows users to retrieve, store, and format emails to be sent.

Security Features

Email servers often use advanced tools to protect information. These include:

Encryption - This is used to protect data sent during transmission to prevent it from being read if intercepted.
Spam filtering - Used to automatically filter potential spam and move it to the junk folder to prevent it from clogging up the main inbox.
Virus scanning - Used to scan email attachments for viruses before they are delivered. If any viruses are discovered, they may be blocked.
Blacklists - If a mail server has been sending lots of spam, malware, or has been continuously engaging in other malicious activities, the company usually adds the mail server to a blacklist, preventing any emails from that mail server from being delivered.