实验
telnet 与 HTTP 实验
telnet命令可以手动编辑和发送报文，Linux 和 Windows 都可以使用
找了一个远程 Linux 服务器进行实验
系统为 CentOS，想要安装telnet命令，root 使用命令：
yum install telnet这里用书上的例子
[root@qmmms ~]# telnet gaia.cs.umass.edu 80
Trying 128.119.245.12...
Connected to gaia.cs.umass.edu.
Escape character is '^]'.
GET /kurose_ross/interactive/index.php HTTP/1.1
Host: gaia.cs.umass.edu
注意最后按两下回车结束，得到结果：
HTTP/1.1 200 OK
Date: Fri, 30 Sep 2022 07:11:13 GMT
Server: Apache/2.4.6 (CentOS) OpenSSL/1.0.2k-fips PHP/7.4.30 mod_perl/2.0.11 Perl/v5.16.3
X-Powered-By: PHP/7.4.30
Set-Cookie: DevMode=0
Transfer-Encoding: chunked
Content-Type: text/html; charset=UTF-8
361c
<!DOCTYPE HTML>
<html>
[...省略...]补充：使用Chrome浏览器，进入开发者模式，进入网络，随便选一个请求，可以看到报文
telnet 与 SMTP 实验
SMTP 是电子邮件使用的应用层协议，同样可以使用telnet命令手动模拟
发邮件一端可以使用远程 Linux 主机
使用 SMTP 协议的邮件服务器比较难找，试了试，学校(DUT)邮箱可以用
用户端需要手动键入的信息有：
HELO xxx.xxx.xxx.x #我的远程主机
MAIL FROM: <用户@xxx.xxx.xxx.x> #发送方
RCPT TO: <用户@对方地址> #收件方
DATA #开始输入正文
. #以单行.作为正文结束
QUIT #结束连接全部实验过程：
[user1@qmmms ~]$ telnet mail.dlut.edu.cn 25
Trying 202.118.66.82...
Connected to mail.dlut.edu.cn.
Escape character is '^]'.
220 mail.dlut.edu.cn ESMTP mail service ready
HELO xxx.xxx.xxx.x
250 OK
MAIL FROM: <user1@xxx.xxx.xxx.x>
250 Mail OK
RCPT TO: <xxxxxxx@mail.dlut.edu.cn>
250 Mail OK
DATA
354 End data with <CR><LF>.<CR><LF>
hello from linux
.
250 Mail OK queued as UEJ2ygBnb+8toTZjKwx_CA--.36240S2
QUIT
221 Bye
Connection closed by foreign host.最后在学校邮箱的垃圾邮件里面找到了这个邮件
补充：就现在而言（2022），大部分电子邮件功能支持都以网页版形式呈现，发邮件可以使用 SMTP 协议，查收邮件 HTTP 协议（通过网页）
telnet 与 POP3 实验
POP3协议，用于接收邮件，同样可以使用telnet命令手动模拟
用户端需要手动键入的信息有：
user 账号
pass 密码
list #列出所有邮件
retr 数字 #查看数字标识的邮件
dele 数字 #删除数字标识的邮件
quit #退出全部实验过程：
[user1@qmmms ~]$ telnet mail.dlut.edu.cn 110
Trying 202.118.66.82...
Connected to mail.dlut.edu.cn.
Escape character is '^]'.
+OK Welcome to coremail Mail Pop3 Server (dlut.edu.cns[627644c969381353b51c9657b72568a4s])
user xxxxxxxxxx@mail.dlut.edu.cn
+OK core mail
pass xxxxxxxxxx
+OK 4 message(s) [1151199 byte(s)]
list
+OK 4 1151199
1 398270
2 741119
3 1682
4 10128
.
retr 3
+OK 1682 octets
Received: from xxxxxxxxx (unknown [xxxxxxxxx])
by mx1 (Coremail) with SMTP id UEJ2ygBnb+8toTZjKwx_CA--.36240S2;
Fri, 30 Sep 2022 15:56:40 +0800 (CST)
hello from linux
X-CM-TRANSID:UEJ2ygBnb+8toTZjKwx_CA--.36240S2
Message-Id:<6336A15F.04A767.07381@dlut.edu.cn>
Authentication-Results: mx1; spf=none smtp.mail=xxx@xxxxxx;
X-Coremail-Antispam: 1UD129KBjDUn29KB7ZKAUJUUUUU529EdanIXcx71UUUUU7v73
VFW2AGmfu7jjvjm3AaLaJ3UjIYCTnIWjp_UUUrS7k0a2IF6F4UM7kC6x804xWl14x267AK
xVWUJVW8JwAFIxvE14AKwVWUJVWUGwA2ocxC64kIII0Yj41l84x0c7CEw4AK67xGY2AK02
1l84ACjcxK6xIIjxv20xvE14v26r1j6r1xM28EF7xvwVC0I7IYx2IY6xkF7I0E14v26r1j
6r4UM28EF7xvwVC2z280aVAFwI0_Jr0_Gr1l84ACjcxK6I8E87Iv6xkF7I0E14v26r1j6r
4UM2vYz4IE57IF64kE628EF7xvwwAS0I0E0xvYzxvE52x082IY62kv0487M2AExVAIFx02
aVAFz4v204v7Mc8Ir4CE8sxKj4xv1VAv77x28xyl52xGzVA2a4k0FcxF6cIjj282cryl5I
8CrVACY4xI64kE6c02F40Ex7xfMcIj64x0Y40En7xvr7AKxVWUJVW8JwAv7VC0I7IYx2IY
67AKxVWUtVWrXwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y4
8IcVAKI48JM4x0aVACjI8F5VA0II8E6IAqYI8I648v4I1lw4AK0VCY07AIYIkI8VC2zVAC
3wAKzVAC0xCFj2AI6cx7M4kE6I8I3I0E14AKx2xKxVC2ax8xMx02cVCv0xWlc7CjxVAKzI
0EY4vE52x082I5MxkI7II2jI8vz4vEwIxGrwCYIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCY
IxAIcVC0I7IYx2IY6xkF7I0E14v26r1j6r4UMxvI42IY6I8E87Iv67AKxVWUJVW8JwCYIx
AIcVC2z280aVCY1x0267AKxVWUJVW8JwCF04k20xvY0x0EwIxGrwCF04k20xvEw4C26cxK
6c8Ij28IcwCFw20E84ACjcxK64kEx2IqYxC7MxCjnVAKz4kxMxC20s026xCaFVCjc4AY6r
1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCjr7xvwVAFwI0_Jr0_Jr4lx4CE17CE
b7AF67AKxVWUJVWUXwCI42IY6xAIw20EY4v20xvaj40_Zr0_Wr1UYxBIdaVFxhVjvjDU0x
ZFpf9x07b6AwxUUUUU=
Date: Fri, 30 Sep 2022 15:57:19 +0800 (CST)
From: xxx@xxxxxx
.
quit
+OK core mail
Connection closed by foreign host.DNS实验
使用远程 LInux 主机
基本介绍
bind是linux系统下的一个DNS服务程序
bind-utils是bind软件提供的一组DNS工具包,可以进行域名解析和DNS调试工作
主要有：dig,host,nslookup,nsupdate
安装工具包
Cent OS 使用命令（root用户）
sudo yum install bind-utils使用
nslookup用于查询DNS的记录，输入一个主机名并发现相应的IP地址
[user1@qmmms ~]$ nslookup www.baidu.com
Server: 100.125.1.250
Address: 100.125.1.250#53
Non-authoritative answer:
www.baidu.com canonical name = www.a.shifen.com.
Name: www.a.shifen.com
Address: 110.242.68.4
Name: www.a.shifen.com
Address: 110.242.68.3[user1@qmmms ~]$ host www.baidu.com
www.baidu.com is an alias for www.a.shifen.com.
www.a.shifen.com has address 110.242.68.3
www.a.shifen.com has address 110.242.68.4[user1@qmmms ~]$ dig www.baidu.com
; <<>> DiG 9.11.4-P2-RedHat-9.11.4-26.P2.el7_9.9 <<>> www.baidu.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 38365
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 0, ADDITIONAL: 1
;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;www.baidu.com. IN A
;; ANSWER SECTION:
www.baidu.com. 399 IN CNAME www.a.shifen.com.
www.a.shifen.com. 21 IN A 110.242.68.3
www.a.shifen.com. 21 IN A 110.242.68.4
;; Query time: 0 msec
;; SERVER: 100.125.1.250#53(100.125.1.250)
;; WHEN: Mon Oct 03 12:54:30 CST 2022
;; MSG SIZE rcvd: 101UDP套接字编程
目标
在本地客户端输入一段字符串
发送给服务器
服务器把字符串改为全大写
发送给本地客户端
本地客户端显示修改过的字符串
准备
当然要两台电脑，或者虚拟机，或者租一个远程服务器
作者租了一个远程服务器，Linux 系统，提前把 python3 之类的环境配置好
如果远程服务器开了防火墙，记得把相关端口允许放行，或者短暂关闭防火墙
客户端代码
code 文件夹下 UDPClient.py
from socket import *
serverName = 'xxx.xxx.xxx.xxx' # 把远程服务器的ip或主机名填这里
serverPort = 12000
clientSocket = socket(AF_INET, SOCK_DGRAM) # 指示网络选择IPv4和UDP
message = input("Input lowercase sentence: ")
clientSocket.sendto(message.encode(), (serverName, serverPort)) # 发送信息
print("have sent message \"", message, "\" to", serverName)
modifiedMessage, serverAddress = clientSocket.recvfrom(2048) # 接收信息，2048表示缓存长度
print(modifiedMessage.decode())
clientSocket.close()服务器端代码
code 文件夹下 UDPServer.py
from socket import *
serverPort = 12000
serverSocket = socket(AF_INET, SOCK_DGRAM) # 指示网络选择IPv4和UDP
serverSocket.bind(('', serverPort)) # 绑定本机ip和端口
print("The server is ready to receive")
while True:
message, clientAddress = serverSocket.recvfrom(2048) # 从客户端接收信息，2048表示缓存长度
print("receive from", clientAddress, ": ", message.decode())
modifiedMessage = message.decode().upper() # 转大写
print("have sent message back: ", modifiedMessage)
serverSocket.sendto(modifiedMessage.encode(), clientAddress) # 发给客户端运行实例
当然，服务器端的代码要先开始运行，然后打开客户端输入
客户端：
Input lowercase sentence: hello world
have sent message " hello world " to xxx.xxx.xxx.xxx
HELLO WORLD服务器端：
The server is ready to receive
receive from ('xxx.xxx.xxx.xxx', xxxx) : hello world
have sent message back: HELLO WORLDTCP套接字编程
目标
在本地客户端输入一段字符串
发送给服务器
服务器把字符串改为全大写
发送给本地客户端
本地客户端显示修改过的字符串
客户端代码
code 文件夹下 TCPClient.py
from socket import *
serverName = 'xxx.xxx.xxx.xxx' # 把远程服务器的ip或主机名填这里
serverPort = 12000
clientSocket = socket(AF_INET, SOCK_STREAM) # 指示网络选择IPv4和TCP
clientSocket.connect((serverName, serverPort)) # TCP 需要先建立连接
message = input("Input lowercase sentence: ")
clientSocket.send(message.encode())
print("have sent message \"", message, "\" to", serverName)
modifiedMessage = clientSocket.recv(2048)
print(modifiedMessage.decode())
clientSocket.close()服务器端代码
code 文件夹下 TCPServer.py
from socket import *
serverPort = 12000
serverSocket = socket(AF_INET, SOCK_STREAM) # 指示网络选择IPv4和TCP
serverSocket.bind(('', serverPort)) # 绑定本机ip和端口
serverSocket.listen(1) # 等待某个用户来连接
print("The server is ready to receive")
while True:
connectionSocket, addr = serverSocket.accept() # 接收连接请求，创建连接
message = connectionSocket.recv(2048).decode() # 从客户端接收信息，2048表示缓存
print("receive from", addr, ": ", message)
modifiedMessage = message.upper()
connectionSocket.send(modifiedMessage.encode()) # 发给客户端
print("have sent message back: ", modifiedMessage)运行实例
客户端：
Input lowercase sentence: hello tcp
have sent message " hello tcp " to xxx.xxx.xxx.xxx
HELLO TCP服务器端：
The server is ready to receive
receive from ('xxx.xxx.xxx.xxx', 6460) : hello tcp
have sent message back: HELLO TCPWebServer套接字编程作业
目标
实现一个 Web 服务器，可以在浏览器上访问
代码
code 文件夹下 WebServer.py
from socket import *
serverSocket = socket(AF_INET, SOCK_STREAM)
serverSocket.bind(('', 80)) # http 默认使用 80 端口
serverSocket.listen(1) # 最大连接数为1
while True:
# Establish the connection
print('Ready to serve...')
connectionSocket, addr = serverSocket.accept()
try:
message = connectionSocket.recv(2048)
filename = message.split()[1]
f = open(filename[1:])
outputdata = f.read()
# Send one HTTP header line into socket
header = ' HTTP/1.1 200 OK\nConnection: close\nContent-Type: text/html\nContent-Length: %d\n\n' % (
len(outputdata))
connectionSocket.send(header.encode())
# Send the content of the requested file to the client
for i in range(0, len(outputdata)):
connectionSocket.send(outputdata[i].encode())
connectionSocket.send("\r\n".encode())
connectionSocket.close()
except IOError:
# Send response message for file not found
header = ' HTTP/1.1 404 Found'
connectionSocket.send(header.encode())
# Close client socket
connectionSocket.close()
为了传输具体的 html 网页，再编写一个简单 html 文件
code 文件夹下 HelloWorld.html
<h1>Hello World!</h1>部署
将两个文件都放在远程服务器上，运行 WebServer.py
最后更新于