计算机网络-第2章邮件报文格式和MIME-同步电大进度

傷城~ 2023-01-13 05:47 169阅读 0赞

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70 1][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70 2][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70 3][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70 4][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70 5][]

**下列关于电子邮件格式的说法错误的是(    )**

*  A.电子邮件内容包括邮件头与邮件体两部分
 *  **B.邮件头中发信人地址(From：)、发送时间、收信人地址(To：)以及邮件主题(Subject)是由系统自动构成的**
 *  C.邮件体就是实际要传送的信函内容
 *  D.MIME协议允许电子邮件系统传输文字、图像、语音与视频等多种信息

### 邮件内容分析 ###

如今很多邮件服务商的邮箱页面如网易邮箱，都可以查看邮件源码。此外如foxmail，outlook等邮件客户端软件也可以查看查看邮件源码。试给出一封真实的邮件的源码（隐私信息可用\*\*\*\*\*代替），分析里面的各部分内容构成。

以下是使用FOXMAIL接收邮件后，得到的邮件源码（.JPG, .TXT）：

\----------------------------------------------------------------

以下部分为邮件服务器添加的邮件头

\----------------------------------------------------------------

Received:from m15-17.126.com (unknown \[220.181.15.17\])

bymx10 (Coremail) with SMTP id PMCowECZWSfPlodRSu6NCw--.779S2;

Mon,06 May 2013 19:41:03 +0800 (CST)

DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=126.com; https:// 域名密钥识别邮件标准，判断垃圾邮件

s=s110527;h=Received:Date:From:To:Subject:Content-Type:

MIME-Version:Message-ID; bh=B57Zfi/+wCVQ61kM9GVkCECk1ax4OZVQDtnW // 不是base64编码

T4lS0x8=;b=XdeYidC7bR1a1l7x3yGAMiMR5ElDx2O4/db2iPrVc0dZ7Y7ANStu     // 不是base64编码

6d9o4l9yVysfwk8vifb0eqyxV2wp28pIlfLEGZbDDpKaLMCaLAbVXdW+2hQl4ojd    // 不是base64编码

sJ7NiAdF1j5X2N87wktFKA8ZK4lPhBYI1yFrNIT+PODg2NzF1CX2FDM=

Received: from zzzzyy91$126.com ( \[202.205.103.22\] ) by ajax-webmail-wmsvr17

(Coremail) ; Mon, 6 May 2013 19:41:01 +0800(CST)

X-Originating-IP: \[202.205.103.22\]                //初始ip地址，同一电脑不同邮箱发邮件，该值相同

\---------------------------------------------------------------------------------------------------------

DATA（以下内容由邮件客户端定义，为DATA命令后输入的内容）

灰色高亮为主要内容

\--------------------------------------------------------------------------------------------------------

Date: Mon, 6 May2013 19:41:01 +0800 (CST)

From: \[base64code\]

To: \[emailaddress\]

Subject: \[base64 code\]

X-Priority: \[integer\]                                          // 邮件优先级

X-Mailer: \[Coremail Webmail Server Version SP\_ntes V3.5 build      // 代理发信客户端

X-CM-CTRLDATA: \[base64 code\]                           // X-邮件服务器自定义的信息段，未知作用

Content-Type:multipart/mixed;                               // 声明邮件内容格式

boundary="----=\_Part\_354288\_309861106.1367840461937"    // 声明邮件内容boundary

MIME-Version: 1.0                                          // 声明MIME版本

Message-ID: <>                                             // X-邮件服务器自定义的信息段

X-CM-TRANSID:                                             //X-邮件服务器自定义的信息段

X-CM-SenderInfo:                                           // X-邮件服务器自定义的信息段

X-Coremail-Antispam:                                       // X-邮件服务器自定义的信息段

\---------------------------------------------------------

以下为邮件的内容

\--------------------------------------------------------

\------=\_Part\_354288\_309861106.1367840461937                 //邮件内容开始

Content-Type: multipart/alternative;                           //邮件内容格式

boundary="----=\_Part\_354290\_1105600126.1367840461937" // 邮件正文boundary

\------=\_Part\_354290\_1105600126.1367840461937              //邮件正文boundary -- 正文开始

Content-Type: text/plain; charset=GBK                        // 邮件正文格式和字符集

Content-Transfer-Encoding: base64

\[base64\]mailcontent (plain)\[base64\]                         //邮件正文（文本格式）编码（base64）

\------=\_Part\_354290\_1105600126.1367840461937              // 邮件正文boundary  --可选HTML格式

Content-Type: text/html; charset=GBK                        //邮件正文格式和字符集

Content-Transfer-Encoding: base64

\[base64\]mailcontent (html)\[base64\]                         //邮件正文（html格式）编码（base64）

\------=\_Part\_354290\_1105600126.1367840461937--           // 邮件正文boundary -- 正文结束

\------=\_Part\_354288\_309861106.1367840461937             // 邮件内容boundary -- 附件1开始

Content-Type: image/jpeg; name="20130324\_224528\_982.jpg" // 附件格式及文件名

Content-Transfer-Encoding: base64

Content-Disposition: attachment;filename="20130324\_224528\_982.jpg"

\[base64\](.jpg)image attachment\[base64\]                         //附件-图片内容编码（base64）

\------=\_Part\_354288\_309861106.1367840461937                  // 邮件内容boundary -- 附件2开始

Content-Type: text/plain; name="window data type.txt"            // 附件格式及文件名

Content-Transfer-Encoding: base64

Content-Disposition: attachment; filename="window datatype.txt"

\[base64\](.txt)plain attachment\[base64\]                         // 附件-文本内容编码（base64）

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20210416102237333.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70 2]: https://img-blog.csdnimg.cn/20210416102239685.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70 3]: https://img-blog.csdnimg.cn/20210416102239461.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70 4]: https://img-blog.csdnimg.cn/20210416102240518.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY=,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FpcXExMzY_size_16_color_FFFFFF_t_70 5]: /images/20221022/828eee9a6d9342cf9a78a4d8a1227d63.png