Linux實現SSH無密碼登陸

時間 2021-03-31

標籤服務器 app ssh ide spa code unicode 欄目 Linux 简体版

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假設服務器 IP 地址爲 192.168.1.1 ，機器名： cluster.hpc.org服務器

客戶端 IP 地址爲 172.16.16.1 ，機器名： p470-2.wangrx.sioc.ac.cnapp

客戶端用戶 yzhao 須要使用 ssh 無密碼登陸服務器的 zhaoy 賬戶ssh

實現原理ide

使用一種被稱爲"公私鑰"認證的方式來進行ssh登陸. "公私鑰"認證方式簡單的解釋是ui

首先在客戶端上建立一對公私鑰（公鑰文件： ~/.ssh/id_rsa.pub ；私鑰文件： ~/.ssh/id_rsa ）
而後把公鑰放到服務器上（ ~/.ssh/authorized_keys ） , 本身保留好私鑰
當ssh登陸時,ssh程序會發送私鑰去和服務器上的公鑰作匹配.若是匹配成功就能夠登陸了

設置以下spa

1 、以 yzhao 用戶登陸客戶機器並在客戶端機器上執行 "ssh-keygen -t rsa" code

( 注：每次執行 "ssh-keygen -t rsa" 產生的私鑰文件都會不一樣 )ci

a ）若是文件 "~/.ssh/id_rsa" 存在，會提示是否覆蓋該文件，此時可選擇 "n" 不覆蓋該文件而使用已有的 id_rsa 文件；若是選擇 "y" 則會從新生成 "~/.ssh/id_rsa" 文件，接下來會提示輸入 passphrase ，回車肯定使用空的 passphrase ，再次回車確認（這裏也能夠輸出 passphrase ，至關於 ssh 時登陸的密碼）。而後會從新生成 "~/.ssh/id_rsa" 文件和 "~/.ssh/id_rsa.pub" 文件（結果以下）。unicode

[yzhao@p470-2 ~]$ ssh-keygen -t rsait

Generating public/private rsa key pair.

Enter file in which to save the key (/disk2/yzhao/.ssh/id_rsa):

/disk2/yzhao/.ssh/id_rsa already exists.

Overwrite (y/n)? y

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /disk2/yzhao/.ssh/id_rsa.

Your public key has been saved in /disk2/yzhao/.ssh/id_rsa.pub.

The key fingerprint is:

6d:a1:17:8a:b6:d2:c0:a1:6c:66:ba:85:0b:7b:9f:0c yzhao@p470-2.wangrx.sioc.ac.cn

b ）若是 "~/.ssh/id_rsa" 文件和 "~/.ssh/id_rsa.pub" 文件不存在則會自動建立新的 "~/.ssh/id_rsa" 文件和 "~/.ssh/id_rsa.pub" 文件， passphrase 設置同上。

[yzhao@p470-2 ~]$ ssh-keygen -t rsa

Generating public/private rsa key pair.

Enter file in which to save the key (/disk2/yzhao/.ssh/id_rsa):

Created directory '/disk2/yzhao/.ssh'.

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /disk2/yzhao/.ssh/id_rsa.

Your public key has been saved in /disk2/yzhao/.ssh/id_rsa.pub.

The key fingerprint is:

54:49:ad:33:b3:ff:71:da:6d:db:78:d0:bb:6a:15:bc yzhao@p470-2.wangrx.sioc.ac.cn

2 、使用 ssh zhaoy@192.168.1.1 登陸到服務器，編輯服務器上 "~/.ssh/authorized_keys" 文件，將客戶端機器上的 "~/.ssh/id_rsa.pub" 文件內容追加到 "~/.ssh/authorized_keys" 文件中。

（注：能夠在客戶端機器上使用如下命令來實現：

cat ~ /.ssh/ id_rsa .pub | ssh zhaoy@ 192.168.1. 1 "cat - >> ~/.ssh/authorized_keys"

cat /root/.ssh/id_rsa.pub|ssh root@192.168.2.168 "cat - >> /root/.ssh/authorized_keys"

此時會要求輸入 zhaoy 在服務器上的登陸密碼，輸入後即會將客戶端機器上的 "~/.ssh/id_rsa.pub" 文件內容追加到服務器上的 "~/.ssh/authorized_keys" 文件中）

若是是首次鏈接服務器會出現如下的提示，確認鏈接並輸入密碼後其餘直接回車肯定。

[yzhao@p470-2 ~]$ ssh zhaoy@192.168.1.1

The authenticity of host '192.168.1.1 (192.168.1.1)' can't be established.

RSA key fingerprint is 94:91:33:01:6b:e7:10:ae:42:ac:ea:5c:8c:bb:f1:18.

Are you sure you want to continue connecting (yes/no)? yes

Warning: Permanently added '192.168.1.1' (RSA) to the list of known hosts.

zhaoy@192.168.1.1's password:

Last login: Fri Dec 21 17:41:38 2007 from 172.16.16.1

Rocks 4.2.1 (Cydonia)

Profile built 03:58 21-Jun-2007

Kickstarted 12:25 21-Jun-2007

Rocks Frontend Node - Our Cluster Cluster

It doesn't appear that you have set up your ssh key.

This process will make the files:

/home/zhaoy/.ssh/id_rsa.pub

/home/zhaoy/.ssh/id_rsa

/home/zhaoy/.ssh/authorized_keys

Generating public/private rsa key pair.

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

Created directory '/home/zhaoy/.ssh'.

Enter passphrase (empty for no passphrase):

Enter same passphrase again:

Your identification has been saved in /home/zhaoy/.ssh/id_rsa.

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

The key fingerprint is:

7e:f6:ab:b0:79:70:cb:c9:f7:40:37:aa:10:4d:4a:ac zhaoy@cluster.hpc.org

3 、若是在第 1 步中使用了空的passphrase ，則能夠跳過第 4 步，此時在客戶端便可以使用 "ssh zhaoy@192.168.1.1" 便可無密碼登陸到服務器；若是第一步中設置了 passphrase ，則繼續執行如下步驟。

4 、若是第 1 步中設置了 passphrase ，則此時須要輸入該 passphrase 登陸服務器。此時前面咱們把輸入密碼變成了輸入passphrase ，這沒有帶來任何方便。可是咱們能夠經過 ssh-agent 來幫助咱們自動輸入 passphrase(只是看起來像是自動輸入而已) ，咱們只要在第一次登陸時輸入一次passphrase, 之後的工做就能夠交給ssh-agent 。在客戶端機器上執行命令 ssh-add ，這裏會提示輸入一次passphrase 。輸入第一步中設置的 passphrase 以後會修改 "~/ .ssh / id_rsa " 文件。再在客戶端執行 "ssh zhaoy@192.168.1.1" 便可無密碼登陸到服務器端。