Linux 环境下未安装telnet，会出现以下错误：[root@RedHat71 ~]# telnet 129.223.248.159

bash: telnet: command not found...

解决方案需要安装telnet服务，此处采用yum install，可以参考 RedHat 7 使用Centos7 的yum源

yum list telnet* 列出安装包

yum install telnet-server 安装server

yum install telnet.* 安装客户端

[root@RedHat71 ~]# telnet 129.223.248.159 12000

bash: telnet: command not found...

[root@RedHat71 ~]# yum list telnet*

Loaded plugins: fastestmirror, product-id, subscription-manager

Loading mirror speeds from cached hostfile

Available Packages

telnet.x86_64                            1:0.17-59.el7                      base

telnet-server.x86_64                     1:0.17-59.el7                      base

[root@RedHat71 ~]# yum install telnet-server

Loaded plugins: fastestmirror, product-id, subscription-manager

Loading mirror speeds from cached hostfile

Resolving Dependencies

--> Running transaction check

---> Package telnet-server.x86_64 1:0.17-59.el7 will be installed

--> Finished Dependency Resolution

Dependencies Resolved

================================================================================

Package               Arch           Version                Repository    Size

================================================================================

Installing:

telnet-server         x86_64         1:0.17-59.el7          base          40 k

Transaction Summary

================================================================================

Install  1 Package

Total download size: 40 k

Installed size: 55 k

Is this ok [y/d/N]: y

Downloading packages:

telnet-server-0.17-59.el7.x86_64.rpm                       |  40 kB   00:01

Running transaction check

Running transaction test

Transaction test succeeded

Running transaction

Installing : 1:telnet-server-0.17-59.el7.x86_64                           1/1

Verifying  : 1:telnet-server-0.17-59.el7.x86_64                           1/1

Installed:

telnet-server.x86_64 1:0.17-59.el7

Complete!

[root@RedHat71 ~]# yum install telnet.*

Loaded plugins: fastestmirror, product-id, subscription-manager

Loading mirror speeds from cached hostfile

Resolving Dependencies

--> Running transaction check

---> Package telnet.x86_64 1:0.17-59.el7 will be installed

--> Finished Dependency Resolution

Dependencies Resolved

================================================================================

Package          Arch             Version                 Repository      Size

================================================================================

Installing:

telnet           x86_64           1:0.17-59.el7           base            63 k

Transaction Summary

================================================================================

Install  1 Package

Total download size: 63 k

Installed size: 113 k

Is this ok [y/d/N]: y

Downloading packages:

telnet-0.17-59.el7.x86_64.rpm                              |  63 kB   00:01

Running transaction check

Running transaction test

Transaction test succeeded

Running transaction

Installing : 1:telnet-0.17-59.el7.x86_64                                  1/1

Verifying  : 1:telnet-0.17-59.el7.x86_64                                  1/1

Installed:

telnet.x86_64 1:0.17-59.el7

Complete!

[root@RedHat71 ~]# telnet 129.223.248.159 12000

Trying 129.223.248.159...

Connected to 129.223.248.159.