1、安装
apt-get install xinetd
apt-get install telnetd
apt-get install telnet

2、修改配置
1）nano /etc/xinetd.d/telnet

填入以下内容

service telnet
{
    disable = no
    flags = REUSE
    socket_type = stream
    wait = no
    user = root
    server = /usr/sbin/in.telnetd
    server_args = -h
    log_on_failure += USERID
}

2）开启root用户
修改etc/pam.d/login

nano etc/pam.d/login
用#号注释掉pam_securetty.so所在行

3、重启服务生效

/etc/init.d/xinetd restart 

然后就可以用telnet了