ssh免密登录

前言

ssh免密登录的应用十分广泛，我们今天要做的是在主机A（hostA）的用户a（usera）上免密登录到主机B（hostB）的用户B（userb）上，所谓免密登录就是在主机A的用户a上生成一个密码为空的**对，然后把公钥传给主机B上的用户b。

参考博客

https://blog.csdn.net/universe_hao/article/details/52296811

操作步骤

1.分别更改用户a和用户b上的hosts文件,新开一个终端

sudo vim /etc/hosts

在主机A的用户a上添加hostB的IP地址：
hostB的IP地址可以在hostB上运行ifconfig来查看

127.0.0.1       localhost
127.0.1.1       hostA
192.168.0.41    hostB
# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

改完之后保存并退出。
在主机B上也是同样操作

2.在主机A的用户a上新开一个终端，输入

ssh-****** -t rsa

按下多次回车键直到看到下图所示

[email protected]:~$ ssh-****** -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/usera/.ssh/id_rsa): 
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/usera/.ssh/id_rsa.
Your public key has been saved in /home/usera/.ssh/id_rsa.pub.
The key fingerprint is:
SHA256:5cgR+Cwn6TYewu6/LETj/T7496ti/8ccPl27tphTNOs [email protected]
The key's randomart image is:
+---[RSA 2048]----+
|       ..        |
|      .  .       |
|       +. .      |
|    o +.+=     o |
|   + + +S .   . o|
|    = *       .o.|
|   o + =     +ooo|
|    o.o = .  .OE.|
|   ..o+=o=o++=o+o|
+----[SHA256]-----+

2.将公钥传给hostB
在主机A上新开一个终端

ssh-copy-id [email protected]

你会看到

[email protected]:~$ ssh-copy-id [email protected]
The authenticity of host 'sikong (192.168.0.41)' can't be established.
ECDSA key fingerprint is SHA256:/YWEksOlzTmh/KTQpiAHFbOuww6ekHv31b34Qj1a2rc.
Are you sure you want to continue connecting (yes/no)? yes
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
[email protected]'s password: 

Number of key(s) added: 1

Now try logging into the machine, with:   "ssh '[email protected]'"
and check to make sure that only the key(s) you wanted were added.

这样就可以免密登录主机B的用户b了。

ssh [email protected]