Telnet协议是TCP/IP协议族中的一员，是Internet远程登陆服务的标准协议和主要方式。它为用户提供了在本地计算机上完成远程主机工作的能力。在终端使用者的电脑上使用telnet程序，用它连接到服务器。终端使用者可以在telnet程序中输入命令，这些命令会在服务器上运行，就像直接在服务器的控制台上输入一样。可以在本地就能控制服务器。要开始一个telnet会话，必须输入用户名和密码来登录服务器。Telnet是常用的远程控制Web服务器的方法。

环境

  • Cisco Packet Tracer 5.3
  • Windows 10

    操作

    操作：按照如图所示连接拓扑图
    image.png
    （1）配置PC IP
    1. PC0 设置
    2. 192.168.1.2/24
    3. PC1 设置
    4. 192.168.1.3/24
    （2）配置交换机VLAN1 IP ``` / part1 为vlan配置ip并开启vlan / Switch>enable Switch#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Switch(config)#interface vlan 1 Switch(config-if)#ip address 192.168.1.1 255.255.255.0 Switch(config-if)#no shutdown

%LINK-5-CHANGED: Interface Vlan1, changed state to up

%LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up Switch(config-if)#

/ Part2 查看已配置的IP / Switch(config-if)#^Z Switch# %SYS-5-CONFIG_I: Configured from console by console

Switch#show running-config … interface Vlan1 ip address 192.168.1.1 255.255.255.0

/ Part3 开启Vlan / Switch#conf t Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)#interface vlan 1 Switch(config-if)#no shutdown

/ Part4 查看Vlan状态 / Switch(config-if)#^Z Switch# %SYS-5-CONFIG_I: Configured from console by console

Switch#show interfaces vlan 1 Vlan1 is up, line protocol is up …

  1. **（3）配置交换机本地登录口令**

/ Part 1 设置明文密码/ Switch#conf t Enter configuration commands, one per line. End with CNTL/Z. Switch(config)#enable password 123 // 注：取消密码可用no enable password

/ Part 2查看设置的密码 / Switch(config)#^Z Switch# %SYS-5-CONFIG_I: Configured from console by console

Switch#show running-config … enable password 123 …

  1. **（4）配置交换机远程登陆及验证**

Switch#conf t Enter configuration commands, one per line. End with CNTL/Z. Switch(config)#line vty 0 Switch(config-line)#password 123 //（Telnet密码为123） Switch(config-line)#login local //（login是开启远程登录密码验证，login local不但要求TELNET密码，还要求提供用户名） Switch(config-line)#

  1. **（5）添加可远程登陆交换机的用户**

/ Part 1 添加用户 / Switch#conf t Enter configuration commands, one per line. End with CNTL/Z. Switch(config)#line vty 0 Switch(config-line)#password 123 Switch(config-line)#login local Switch(config-line)# Switch(config-line)#exit Switch(config)#username admin password admin

/ Part 2 查看添加的用户 / Switch(config)#exit Switch# %SYS-5-CONFIG_I: Configured from console by console

Switch#show running-config … username admin password 0 admin …

  2. **（6）测试连接**

// 在PC0的CMD中测试 / Part 1 Ping交换机 / PC>ping 192.168.1.1

Pinging 192.168.1.1 with 32 bytes of data:

Reply from 192.168.1.1: bytes=32 time=5ms TTL=255 Reply from 192.168.1.1: bytes=32 time=5ms TTL=255 Reply from 192.168.1.1: bytes=32 time=6ms TTL=255 Reply from 192.168.1.1: bytes=32 time=6ms TTL=255

Ping statistics for 192.168.1.1: Packets: Sent = 4, Received = 4, Lost = 0 (0% loss), Approximate round trip times in milli-seconds: Minimum = 5ms, Maximum = 6ms, Average = 5ms

/ Part 2 Telnet 连接交换机 / PC>telnet 192.168.1.1 Trying 192.168.1.1 …Open

User Access Verification

Username: admin Password: Switch>

  1. **（7）配置多用户连接**

// 在PC0连接的前提下，再使用PC1尝试连接 / Part 1 PC1 Ping Switch / PC>ping 192.168.1.1

Pinging 192.168.1.1 with 32 bytes of data:

Request timed out. Reply from 192.168.1.1: bytes=32 time=6ms TTL=255 Reply from 192.168.1.1: bytes=32 time=6ms TTL=255 Reply from 192.168.1.1: bytes=32 time=5ms TTL=255

Ping statistics for 192.168.1.1: Packets: Sent = 4, Received = 3, Lost = 1 (25% loss), Approximate round trip times in milli-seconds: Minimum = 5ms, Maximum = 6ms, Average = 5ms

/ Part 2 PC1 Telnet 连接Swithc / PC>telnet 192.168.1.1 Trying 192.168.1.1 …Open

[Connection to 192.168.1.1 closed by foreign host] // 连接失败，因为交换机vty设置只能同时打开一个会话，下面设置一下，使两台PC可同时访问

/ Part 3 修改Tenlet配置 / // 可直接在PC0直接进行 Switch#conf t Enter configuration commands, one per line. End with CNTL/Z. Switch(config)#line vty 0 1 Switch(config-line)#password 123 Switch(config-line)#^Z

/ Part 4 重新尝试Part 2 / PC>telnet 192.168.1.1 Trying 192.168.1.1 …Open

User Access Verification

Password: Switch> // 成功 ```

实验文件

为交换机配置并连接TELNET.zip