table of Contents
One. Purpose
Familiar with Packet Tracer tool. Analysis caught application layer protocol packets, application layer protocol-depth understanding, including syntax, semantics, timing.
two. Content Experiments
Use Packet Tracer, properly configured network parameter, packet data capture and analysis application layer protocol, the protocol comprising DNS, FTP, DHCP, stmp, pop3. Steps include:
(1) establish a network topology
(2) Configuration Parameters
(3) Ethereal
(4) Analysis of data packets
three. experimental report
Before writing the report, read: submit jobs to some of the considerations of the class blog .
(1) Give your personal information at the beginning of Bowen
- Name Wu Han Yang
- School number 201 821 121 073
- 1813 class computing
(2) establish a network topology
On the left is PC-PT client, server-side right side Server-PT
3.1 DNS
(3) Configuration Parameters
1. Client address (192.168.1.73)
2. The server address (192.168.1.74)
3. New DNS domain name
4 . Set the DNS service pc0
(4) capture and analyze packets captured
Request packet:
The client sends a request message to the server, requesting the domain name hanyang.wu
Response message:
TYPE represents the type of query
CLASS represent the query class
TTL ( Time to Live ) represents the survival time, in seconds
Resource data length LENGTH represents
3.2 FTP
(1) Configuration Parameters
1. The client's ip address is set to 192.168.1.73, the server's ip address is 192.168.1.74.
2. Set a user name and password (by default there is a connection account password of FTP)
(2) capture and analyze packets captured
1. Open a command line to access the server, using ftp server on a host connection
2. Ethereal
3. Analysis of the captured data packet ftp
服务器发送响应报文：Welcome to PT Ftp serve
输入用户名：cisco
Code 331：输入了用户名，等待用户输入密码
FTP Command:PASS：密码输入成功
登陆成功
3.3 DHCP
1.将PC端的IP获取方式从静态改成DHCP获取
2.将服务器的DHCP的services打开 并且配置好参数
3.抓包并分析抓到的数据包
主机分配得到的ip地址为192.168.1.1，而服务器分配的地址为192.168.1.73
因为服务器的地址为静态，因此该地址为我们自己设置，而主机的地址为动态，因此分配到空闲的地址为192.168.1.1
3.4 smtp和pop3
首先，打开服务器email的smtp和pop3的service，并且设置user的账号和密码。
然后配置服务器的DNS，添加两个域名地址，一个一会用于发送email一个用于接收。*（两者的地址后缀应该相同）
配置主机的ipconfig，DNS填写为服务器的ip地址。
接着配置主机email的信息
填写的email address后缀应和发送地址和接收地址的后缀相同，否则发送不成功。
配置完后就可以发送邮件（邮箱地址只要后缀相同即可）。
发送后，取消断点，截取pop3和smtp数据包
发现只有smtp的数据包，接着点击receive
就发现有pop3的数据包。接着分析数据包。
smtp
pop3
*email是应用tcp传输
*PORT：是为TCP协议通信提供服务的端口
4.实验中产生的疑问
为什么在配置接收邮箱的地址后缀应该与接收邮件的域名后缀相同？
因为该邮箱接收邮件时，接收地址应被接受邮件的域名所识别，从而将邮件转发给接受邮箱，而地址的识别方法是靠地址后缀所识别。