Linux机器相互登录

主机名	IP地址
centos-01	192.168.150.128
centos-02	192.168.150.129

CentOS-01连接CentOS-02（普通方式）

CentOS-01

[root@centos-01 ~]# ssh 192.168.150.129
The authenticity of host '192.168.150.129 (192.168.150.129)' can't be established.
ECDSA key fingerprint is SHA256:tUzP+aYEwLklzTHTN5A9dzFfXb+4E9hdOmD1M2jml0s.
ECDSA key fingerprint is MD5:5f:f2:ca:7f:3c:f1:21:f0:0c:16:25:61:7f:83:ca:6b.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added '192.168.150.129' (ECDSA) to the list of known hosts.
root@192.168.150.129's password: 
Last login: Thu Jan 18 12:56:31 2018 from 192.168.150.1

CentOS-02

[root@centos-02 ~]# w
 12:59:32 up 4 min,  2 users,  load average: 0.13, 0.31, 0.16
USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
root     pts/0    192.168.150.1    12:56    4.00s  0.06s  0.04s w
root     pts/1    192.168.150.128  12:59   19.00s  0.01s  0.01s -bash

CentOS-01

[root@centos-02 ~]# logout
Connection to 192.168.150.129 closed.
[root@centos-01 ~]#

CentOS-02免密钥登录CentOS-01(SSH登录)

CentOS-02

[root@centos-02 ~]# 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:
SHA256:RfjueL/pQSL51ms5J7DK5O80C3kUGNcjPqNAZP6srzw root@centos-02
The key's randomart image is:
+---[RSA 2048]----+
|     .o ..o.     |
|     o. .=. o    |
|     .. .oo. .   |
|      .o o=.     |
|       .Sooo.    |
|       ..=o+     |
|      . +o*oo.   |
|     .E=.=+o=+.  |
|      oo==++*=   |
+----[SHA256]-----+
[root@centos-02 ~]#
[root@centos-02 ~]# ls /root/.ssh/
authorized_keys  id_rsa  id_rsa.pub
[root@centos-02 ~]# cat /root/.ssh/id_rsa.pub 
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCUhPCnFjVORQdYvn6wmJUc6LPQRwaF4lraCGbCm2lj3l0rp+jDgTSST5WZ4qOus9Vp4pko0y1Savirp1emHHz2SZVih4NLqyoeb8AJjqgoGjaY2jmX0Mrc5qDIhisZjMn/+Juje7gURsocRnVCKVKBSMBOKMUocatNyBWbdswuKjJK4tsLJbPd/Y3UVXqIqv3wU9RrWKMUCiJUe7HlDZoFJp9KNx7GLjhrl0tjxsChqilODDvtlRbzA6ojJggNlmcXVcs8Bj7kcOFXwKvWEQwjEk1Vh9T+lI/oSKr/c/Pqc5zTL2LgY/0U88lui8MCrn3doA7jluwH+VVFUOA4BPPd root@centos-02

把公钥内容复制到CentOS-01上去

CentOS-01

[root@centos-01 ~]# vi /root/.ssh/authorized_keys

添加

#centos-02
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQCUhPCnFjVORQdYvn6wmJUc6LPQRwaF4lraCGbCm2lj3l0rp+jDgTSST5WZ4qOus9Vp4pko0y1Savirp1emHHz2SZVih4NLqyoeb8AJjqgoGjaY2jmX0Mrc5qDIhisZjMn/+Juje7gURsocRnVCKVKBSMBOKMUocatNyBWbdswuKjJK4tsLJbPd/Y3UVXqIqv3wU9RrWKMUCiJUe7HlDZoFJp9KNx7GLjhrl0tjxsChqilODDvtlRbzA6ojJggNlmcXVcs8Bj7kcOFXwKvWEQwjEk1Vh9T+lI/oSKr/c/Pqc5zTL2LgY/0U88lui8MCrn3doA7jluwH+VVFUOA4BPPd root@centos-02

保存退出

查看SELinux状态

[root@centos-01 ~]# getenforce 
Enforcing

SELinux是打开的

临时关闭

[root@centos-01 ~]# setenforce 0
[root@centos-01 ~]# getenforce 
Permissive

CentOS-02

[root@centos-02 ~]# ssh 192.168.150.128
Last login: Thu Jan 18 15:46:51 2018 from 192.168.150.129
[root@centos-01 ~]# logout
Connection to 192.168.150.128 closed.
[root@centos-02 ~]#