http://blog.csdn.net/u012259256/article/details/67639982
http://blog.csdn.net/wfh6732/article/details/55062016
问题：
-bash: telnet: command not found
查找Telnet包 yum list |grep telnet yum list |grep xinetd 发现有telnet-server.x86_64这个源 yum install telnet-server.x86_64 -y yum install xined
安装成功，再搜索遍看是否已经写入环境中
rpm -qa | grep telnet #
yum list |grep telnet # @base的代表已经安装了的.
开启service：
systemctl start telnet.socket
systemctl start xinetd
开启23端口号
查询端口号：firewall-cmd --query-port=23/tcp 是否开启！ 开永久端口号：firewall-cmd --add-port=23/tcp --permanent
开机自启
systemctl enable xinetd.service
systemctl enable telnet.socket