CentOS:

[root@clovem ~]# yum install telnet-server -y  //安装telnet服务端[root@clovem ~]# cat /etc/xinetd.d/telnet     //开启telnet的托管服务# default: on# description: The telnet server serves telnet sessions; it uses \#unencrypted username/password pairs for authentication.service telnet{flags= REUSEsocket_type= stream wait= nouser= rootserver= /usr/sbin/in.telnetdlog_on_failure+= USERIDdisable= no                              //将yes改为no}[root@clovem ~]# service xinetd restart          //重启托管服务使配置文件生效

如下操作使root用户登录生效

[root@clovem ~]# mv /etc/securetty /etc/securetty.bak

这样， root 就可以直接进入 Linux 主机了。不过，建议不要这样做。也可以在普通用户进入后，切换到root用户,拥有root的权限。

Red Hat Enterprise Linux AS release 4

需要修改：krb5-telnet

[root@rawlnx ~]# cat /etc/xinetd.d/krb5-telnet# default: off# description: The kerberized telnet server accepts normal telnet sessions, \# but can also use Kerberos 5 authentication.service telnet{flags= REUSEsocket_type= streamwait= nouser= rootserver= /usr/kerberos/sbin/telnetdlog_on_failure+= USERIDdisable= no}

配置完成，重启xinetd 服务

solaris：将本文件的CONSOLE一行注释，直接生效

-bash-3.00# cat /etc/default/login |grep CONSOLE# If CONSOLE is set, root can only login on that device.#CONSOLE=/dev/console

---