ssh免密码登录远程server

1、server A想和server B建立连接，则应将server A的公钥（id_dsa.pub或者id_rsa.pub）放在server B的/root/.ssh/authorized_keys中

2、server A 通过ssh连接server B，但是ssh认证失败，原因是server A中保存错误的server B的信息，解决办法，在known_hosts中定位line 28，删除该行即可

set nu #显示行号

:28 #定位

dd #删除该行

3、server A免密码登陆server B方法

server A端执行如下操作

root@f49:~# cd ~/.ssh/

root@f49:~/.ssh#ssh-keygen -t rsa

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:djVh+Yhu88UNaBFVm95b1cRiUycOvuTMNg+sSncyC/kroot@f49

The key's randomart image is:

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

|           =+o+=|

|          oo++o*|

|          .=*.=o|

|         .B+o+ o|

|       S...X. +o|

|      . o+o +o +|

|       +.=o.... |

|      . = =.    |

|       . E      |

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

root@f49:~/.ssh# ls

id_rsa  id_rsa.pub  known_hosts

root@f49:~/.ssh# cp id_rsa.pub authorized_keys //实现ssh localhost免密码登陆，能识别自己。

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root@f63:~/.ssh# scp root@192.168.0.49:/root/.ssh/id_rsa49.pub ./

root@192.168.0.49's password:

id_rsa49.pub                                              100%  390    0.4KB/s   00:00   

root@f63:~/.ssh# cat id_rsa49.pub >> authorized_keys  //将f49的公钥添加到f63的authorized_keys文件中，使f63能认证f49，从f49server端实现免密钥登录f63。