An email server or mail server is a kind of computer that stores all electronic email content and conversations. It is also responsible for moving an email message from the sender to the recipient. In other words, the server facilitates sending and receiving email. A mail server is a post office’s digital equivalent, storing all letters it receives. In case of a post office, the postman delivers the letters. With mail servers, the Internet plays the role of a postman. Past email conversations, sending and receiving email, etc. are stored on and managed by mail servers.

Mail Server’s Role in an Email’s Journey

When an email message is sent, the mail client (Gmail or Yahoo) connects to the outgoing mail server (SMTP server) and provides it information such as sender and receiver email address, mail message body and attachments (if any), etc. Once the sender information is cleared, the server contacts the SMTP server at the recipient’s side. Once everything is okay, the mail in the SMTP server is picked up by the POP3 server. The recipient’s mail client downloads the message and notifies the recipient. SMTP and POP3 servers use the SMTP and POP protocol/language to get the job done.

The names of the outgoing and incoming mail servers must be specified before using an email service. A user only has access to mail servers provided by a particular Internet service provider (ISP). And a mail server has a limit to the IP addresses it acknowledges, which is why ISPs offer mail servers to only those IP addresses that fall within their range. However, there could be exceptions to this rule.

Owning/Renting a Mail Server

People have the option to choose between owning and renting a mail server. When owning the server, the individual manages a particular domain’s email and is also responsible for installing and running the software. Configuring a mail server can be complicated, and troubleshooting things when something goes wrong can be an even bigger pain. If you’re technically-savvy, the configuration and remedying act should not be a problem.

The configuration aspect basically entails selecting the mail protocol (SMTP and POP/IMAP), entering hostnames or IP addresses for incoming and outgoing mail servers, their port numbers, adding spam filter/antivirus, testing connection, etc. Another challenge is ensuring the mail server is off blacklists that comprise IP addresses notorious for sending junk mail or spam.

An external or third-party mail service for an annual or monthly fee offers managed email servers, taking care of all the maintenance, hosting and troubleshooting work. Some level of control may get lost but that is something people with little knowledge about setting up and operating a mail server would not be worried about. Some third-party mail service options are Google Apps, Office 365, Zoho and FastMail.