1、ssh服务生成新的公钥和私钥[root@rhel6_80 ~]# ssh-keygen 
Generating public/private rsa key pair.
Enter file in which to save the key (/root/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /root/.ssh/id_rsa.     #私钥存放地址
Your public key has been saved in /root/.ssh/id_rsa.pub.     #公钥存放地址
The key fingerprint is:
3e:ff:b3:68:de:e7:06:1b:fb:21:49:44:bb:38:76:e3 root@rhel6_80
The key's randomart image is:
+--[ RSA 2048]----+
|            .    |
|           . .   |
|            o    |
|           o .   |
|        S + =    |
|       . . =oo   |
|        o   E=.  |
|         o.o+.o. |
|         o+.+Bo  |
+-----------------+
[root@rhel6_80 ~]# ls .ssh/

id_rsa  id_rsa.pub  known_hosts        #id_rsa私钥   id_rsa.pub公钥。

[root@rhel6_80 ~]# ssh-copy-id -i /root/.ssh/id_rsa.pub root@192.168.3.84   #将公钥发布给84服务器后，80再次连接84就不需要再输入密码
[root@rhel6_80 ~]# ssh 192.168.3.84

Last login: Thu May 19 20:33:21 2016 from 192.168.3.130

警告！哈哈哈哈哈哈

PATH=/root/:/usr/lib64/qt-3.3/bin:/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin        #无需输密码连接成功

[root@rhel6_84 ~]# 

[root@rhel6_80 ~]# yum -y install xinetd
[root@rhel6_80 ~]# vim /etc/xinetd.conf    #配置文件

[root@rhel6_80 ~]# yum -y install telnet-server tftp-server rsync           #安装测试用程序，测试被xinetd管理的程序

# default: off

# description: The rsync server is a good addition to an ftp server, as it \
[root@rhel6_80 ~]# vim /etc/xinetd.d/rsync      #启动rsync服务

#       allows crc checksumming etc.

service rsync

{

        disable = no             #这里改成no，表示启动xinetd

        flags           = IPv6

        socket_type     = stream

        wait            = no

        user            = root

        server          = /usr/bin/rsync

        server_args     = --daemon

        log_on_failure  += USERID
[root@rhel6_80 ~]# service xinetd restart                            #启动xinetd服务

停止 xinetd：                                              [失败]

正在启动 xinetd：                                          [确定]

[root@rhel6_80 ~]# netstat -anptu |grep 873                            #检测是否正常监听873端口，有标示rsync服务正常启动。

tcp        0      0 :::873                      :::*                        LISTEN      3945/xinetd