检查是否安装了telnet服务

[root@localhost app]# rpm -qa | grep telnet

若返回为空，则证明没有安装
YUM 安装

[root@localhost app]# yum -y install telnet telnet-server

启动telnet服务
编辑/etc/xinetd.d/telnet文件，将disable 改为no

[root@localhost app]# vim /etc/xinetd.d/telnet 

# default: on
# description: The telnet server serves telnet sessions; it uses \
#      unencrypted username/password pairs for authentication.
service telnet
{flags          = REUSEsocket_type    = streamwait          = nouser          = rootserver         = /usr/sbin/in.telnetdlog_on_failure  += USERIDdisable        = no
}

[root@localhost app]# service xinetd restart
停止 xinetd：                                       [失败]
正在启动 xinetd：                                   [确定]
设置telnet 服务开机自启动
[root@localhost app]# chkconfig telnet on