1，检查是否安装 telnet-server和xinetd
- rpm -qa telnet-server
- rpm -qa xinetd
2，如果没有安装过就安装 查找yum
- yum list |grep telnet
- yum list |grep xinetd
3,执行安装语句
- yum -y install telnet-server.x86_64
- yum -y install telnet.x86_64
- yum -y install xinetd.x86_64
4,设置开机自启：
- systemctl enable xinetd.service
- systemctl enable telnet.socket
5,开启service：
- systemctl start telnet.socket
- systemctl start xinetd