[root@edunode248 home]# yum list |grep telnet
telnet.x86_64                               1:0.17-64.el7              @base
telnet-server.x86_64                        1:0.17-64.el7              base

#只安装客户端即可
[root@edunode248 home]# yum install telnet.x86_64

### 下面这种情况说明端口没有映射
[root@edunode248 home]# telnet 124.152.228.81 1194
Trying 124.152.228.81...
telnet: connect to address 124.152.228.81: Connection refused

### 下面这种表示端口映射成功
[root@edunode248 home]# telnet 124.152.228.81 40080
Trying 124.152.228.81...
Connected to 124.152.228.81.
Escape character is '^]'.
Connection closed by foreign host.