root@mytest:~# 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.

Your public key has been saved in /root/.ssh/id_rsa.pub.

The key fingerprint is:

7e:0f:dc::2e:d3:e0::c0:5f:fe:cf:e9:7a:f7: root@mytest

The key's randomart image is:

+--[ RSA ]----+

|     ..          |

|      ..  .      |

|       ..oo .    |

|        .+.+ .   |

|        S +.o .  |

|       . . +..   |

|        . + .o E |

|         . o  * o|

|            o+.oo|

+-----------------+

root@mytest:~# sz /root/.ssh/id_rsa.pub 

# ssh-copy-id -i /root/.ssh/id_rsa.pub danny@12.1.1.2

danny@12.1.1.2's password:      //输入主机B用户danny的登录密码

[root@B danny]# mkdir .ssh

[root@B danny]# cd .ssh/

[root@B .ssh]# touch authorized_keys

[root@B .ssh]# ls

authorized_keys

[root@B .ssh]# cat /home/danny/id_rsa.pub >authorized_keys

root@mytest:/# ssh danny@IP_B