What is a mail server

Many people are familiar with servers, but everyone is unfamiliar with mail servers. So what is a mail server? PHP Chinese website will introduce you to the mail server. [Recommended reading: What is a server】

1: What is a mail server

The mail server is a device used to manage email sending and receiving, and is also the core content of the email system. The mail server has an SMTP server for sending emails and a POP3 server for receiving emails that work together, and provides users with the function of receiving emails. Mail servers are more secure than regular free mailboxes and have always been used by corporate companies.

2: Mail server introduction

Mail is operated by separate server software, which are used separately Send and receive. In order to send and receive emails, servers with multiple roles work together. The email server is divided into an SMTP server for email delivery/transmission and a POP3 server responsible for email reception. In addition, in order to establish the mail delivery mechanism, the IP address corresponding to the address on the Internet of the destination mail server (SMTP server) is determined based on the mail address domain name. Of course, a DNS server is required. These servers play an important role and set up the mail system, for example, if you are using web mail, you have to link the web server further.

Three: Mail server role

1.SMTP server role

Simple Mail Transfer Protocol (SMTP) just sends and delivers to another server The mechanism of mail. Users use email software, etc. to create emails and send them. After receiving the user's mail, the SMTP server requests the DNS server to determine the target mail server from the domain portion of the target mail address and then delivers the mail to that server.

2.POP3 server role

The POP3 server role is easy to understand in the postal system. Assuming that it operates with the post office box, the mail sent by the SMTP server will eventually be delivered to the POP3 server. In a POP3 server, each email address has an email box, called a mailbox, and stores emails to be delivered. Users use email software to access messages in this mailbox. The role of the POP3 server is to provide this series of mechanisms. POP3 uses port 110, while POP over SSL uses port 995 for encryption.

The above is a complete introduction to what a mail server is. If you want to know more about HTML video tutorial, please pay attention to the php Chinese website.

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