Mail Server

Mail server is a kind of used to responsible for E-mail transceiver management equipment. Its free E-mail addresses than network more safe and efficient, so has been the necessary equipment company.

introduction

E-mail is the Internet is one of the most popular applications. As the postman delivered mail distributed as, E-mail is asynchronous, meaning that people are at the convenient time send and reading email and do not need to advance and others synergy. And the traditional mail is different, E-mail is fast, and easy to distribute, and low cost. In addition, the modern electronic mail messages can contain hyperlinks, HTML text, image, sound and even video data. We will in this paper view in the core of Internet E-mail application layer protocol. But in the thorough discussion of these agreements, let us first planner before the Internet mail system and its important components.

structure

Mail system consists of three main components comprise: user agent, Mail server and simple Mail Transfer Protocol (simple Protocol, referred to as' E-mail SMTP). We will in this context that each A1ice parts: the sender to accept successor Bob sends an email message. User agent allows users to read, reply, forwarding, preservation and write E-mail messages (email user agent sometimes called mail reader, but in this paper we avoid to use the phrase). Alice finish writing E-mail message, her user agent write this message sent to mail server by this email servers again this information into the queue out news. When Bob want to read E-mail news, his user agent from him in the email server mailbox obtained in the mail. The late 1990s, the graphical user interface (GUI) email user agent in popularity, they allow users to read and write the multimedia message. Current user agents including Outlook, foxmail etc. Public domain and many text-based electricity in email user agent, including E-mail, pine and elm.

Mail server principle

Mail server constitute the core of electronic mail system. Each recipient has a is located in an email server mailbox (it). Bob mailbox for management and maintenance has been sent to his E-mail message. An E-mail message from the typical journey of the sender, a user agent began to swim a sender email server, transfer to the recipient's email server, and delivery to the recipient mailbox. When Bob want to check its own mailbox of email message, deposit this mailbox mail server will offer him user name and password authentication him. Alice's mail server still have to deal with Bob's mail server failures. If Alice's mail server cannot bring E-mail message immediately delivered Bob mail server, A1ice server just put them in the message queue (macro) after queue, try again delivery. This kind of try every 30 minutes or so often perform one: if after a several days still not trying to succeed, the server will give the news to remove from the message queue, also with another E-mail notifications sender (i.e., Alice).

The simple mail transfer protocol (SMTP) is the Internet E-mail system first application-layer protocol. It USES the TCP providing reliable data transmission service to mail message from a sender email server transmitted to the recipient's email server. As with most application-layer protocol, SMTP also exist two end: in the sender email server execution client and in the recipient's email server execution of the server. SMlP client and server in every email servers running at same time. When a mail server to other mail server in E-mail messages, it is in the running as SMTP customers. When a mail server from the other mail server receives the E-mail message, it is as SMTP server is running.