[Linux] 리눅스 시스템 간 SSH Key를 통한 인증 로그인 설정

1. Destination Server 에서 아래 명령어를 통해 인증 키 생성, 옵션을 통해 인증키의 인증방식을 수정 가능

[root@Destination Server ~]# ssh-keygen

Generating public/private rsa key pair.

Enter file in which to save the key (/root/.ssh/id_rsa): 

Created directory '/root/.ssh'.

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:

SHA256:6MLun8gQLmRbAqPGH5XKw+WFX3wKdfGC8mm+ziyWyUs root@Destination Server.net

The key's randomart image is:

+---[RSA 2048]----+

|         . o.    |

|      o o o .    |

|o    = + + o .   |

|+.o = o.= + .    |

|.*.B ...S=       |

|+.=oo.  o        |

|..o.o oEo.       |

| . + o.Bo .      |

|   .=.+.+=       |

+----[SHA256]-----+

[root@Destination Server /]# cd ~/.ssh/

[root@Destination Server .ssh]# vi ./authorized_keys <- Source 서버에서 생성한 키를 삽입 할 목적

2. Source가 될 리눅스 서버에서 아래 명령어 수행

[root@Source Server /]# 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:

5e:32:7c:5e:67:58:5c:31:7d:c0:19:20:83:4e:c2:88 root@Source Server

The key's randomart image is:

+--[ RSA 2048]----+

|   . o   .o .oo*+|

|  E . o o  o .o.+|

|       +      o .|

|       ..    o   |

|        S o o o  |

|       . * . o   |

|        . .      |

|                 |

|                 |

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

[root@Source Server /]# cat ~/.ssh/*pub

ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDmk5uEnZOcMC8OtWyyu/FLQmqyla5VbSo2yR1bRwgDP4zcxDkm3bvKZAmRbQYOKzOum++jOUZBliW141wXhV+LqGAvg2vYOa5y06Gfdlw6pJwVA8/1/H/BBPFCpYGShUJNMxw89Y/Ct3gcH1f0umcxzaJRvhzpu0z/FDmr3ZFyMT4oQ+4pHz6IgtFKiDCzQZJbmm5i9zLBoGGyRtNYaQyF46YB+u567hU1SIbMRofzaWFqePt6ty0XboPmIdcgPD0HEjLDCWTttXgPdprK54m7MZP2SMR3EGTKRMsSp48ssMrQompMkP2HXHTEI3wK/Bia7gmx+VB+CpyQRMsV/eQB root@Source Server

3. Source가 될 리눅스 서버에서 해당 인증키를 복사하여 Destination Server authorized_keys 에 등록

4. 접속 테스트

[root@Source Server /]# ssh 192.168.0.241

Last login: Mon Apr  3 21:34:01 KST 2017 on cron

Last login: Mon Apr  3 21:34:55 2017 from 192.168.0.242

[root@Destination Server ~]# 

5. 원격 명령어 수행 테스트

[root@Source Server /]# ssh 192.168.0.241 free

             total       used       free     shared    buffers     cached

Mem:       4059404    3643352     416052          0       4752     423612

-/+ buffers/cache:    3214988     844416

Swap:            0          0          0

[root@Source Server /]# 

[root@Source Server /]# ssh 192.168.0.241 hostname

Destination Server