Internet Technologies 简明教程
E-mail Overview
电子邮件是一种服务，允许我们在互联网上以电子模式发送邮件。它提供了一种经济、高效且实时的信息分发方式。
Email is a service which allows us to send the message in electronic mode over the internet. It offers an efficient, inexpensive and real time mean of distributing information among people.
E-Mail Address
每个电子邮件用户都会为其电子邮件帐户分配一个唯一名称。此名称称为电子邮件地址。不同的用户可以根据电子邮件地址发送和接收邮件。
Each user of email is assigned a unique name for his email account. This name is known as E-mail address. Different users can send and receive messages according to the e-mail address.
电子邮件通常采用 username@domainname 形式。例如， webmaster@tutorialspoint.com 是一个电子邮件地址，其中 webmaster 是用户名，tutorialspoint.com 是域名。
E-mail is generally of the form username@domainname. For example, webmaster@tutorialspoint.com is an e-mail address where webmaster is username and tutorialspoint.com is domain name.
E-mail Message Components
电子邮件消息包含以下组成部分：电子邮件标题、问候、文本和签名。这些组成部分在以下示意图中进行描述：
E-mail message comprises of different components: E-mail Header, Greeting, Text, and Signature. These components are described in the following diagram:
E-mail Header
电子邮件信息的前面五行被称为电子邮件头。头部部分包括以下字段：
The first five lines of an E-mail message is called E-mail header. The header part comprises of following fields:
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From
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Date
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To
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Subject
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CC
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BCC
From 字段表示发件人地址，即谁发送了电子邮件。
The From field indicates the sender’s address i.e. who sent the e-mail.
Date 字段表示发送电子邮件的日期。
The Date field indicates the date when the e-mail was sent.
To 字段表示收件人地址，即向谁发送了电子邮件。
The To field indicates the recipient’s address i.e. to whom the e-mail is sent.
Subject 字段表示电子邮件的目的。它应准确且切中要害。
The Subject field indicates the purpose of e-mail. It should be precise and to the point.
CC 代表抄送。它包括我们希望了解信息但并非明确的收件人的收件人地址。
CC stands for Carbon copy. It includes those recipient addresses whom we want to keep informed but not exactly the intended recipient.
BCC 代表密送。当我们不希望一位或多位收件人知道其他人在邮件中被抄送时，我们使用它。
BCC stands for Black Carbon Copy. It is used when we do not want one or more of the recipients to know that someone else was copied on the message.
问候是实际信息的第一句话。例如。尊敬的先生或各位、等等。
Greeting is the opening of the actual message. Eg. Hi Sir or Hi Guys etc.
它表示消息的实际内容。
It represents the actual content of the message.
这是电子邮件消息的最后部分。它包括发件人的姓名、地址和联系电话。
This is the final part of an e-mail message. It includes Name of Sender, Address, and Contact Number.
Advantages
电子邮件被证明是强大而可靠的通信媒介。以下是 E-mail: 的好处：
E-mail has prooved to be powerful and reliable medium of commmunication. Here are the benefits of E-mail:
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Reliable
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Convenience
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Speed
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Inexpensive
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Printable
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Global
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Generality
Reliable
许多邮件系统会通知发件人电子邮件是否未送达。
Many of the mail systems notify the sender if e-mail message was undeliverable.
Convenience
不需要书信和邮票。人们不必去邮局。但是，发送或接收邮件并不需要所有这些东西。
There is no requirement of stationary and stamps. One does not have to go to post office. But all these things are not required for sending or receiving an mail.
Speed
电子邮件非常快。然而，速度还取决于底层网络。
E-mail is very fast. However, the speed also depends upon the underlying network.
Disadvantages
除了电子邮件的几种好处外，也存在一些缺点，如下所述：
Apart from several benefits of E-mail, there also exists some disadvantages as discussed below:
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Forgery
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Overload
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Misdirection
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Junk
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No response
Forgery
电子邮件无法防止伪造，也就是说，冒充发件人，因为发件人通常不会以任何方式进行身份验证。
E-mail doesn’t prevent from forgery, that is, someone impersonating the sender, since sender is usually not authenticated in any way.